GSFC magnetic field experiment Explorer 43. [describing magnetometer, data processor, and telemetry

NASA Technical Reports Server (NTRS)

Seek, J. B.; Scheifele, J. L.; Ness, N. F.

1974-01-01

The magnetic field experiment flown on Explorer 43 is described. The detecting instrument is a triaxial fluxgate magnetometer which is mounted on a boom with a flipping mechanism for reorienting the sensor in flight. An on-board data processor takes successive magnetometer samples and transmits differences to the telemetry system. By examining these differences in conjunction with an untruncated sample transmitted periodically, the original data may be uniquely reconstructed on the ground.

Feasibility Study for an Autonomous UAV - Magnetometer System

DTIC Science & Technology

2007-11-01

collect data from multiple magnetometers at high sampling rates (~100 Hz), and associated with these acquisition systems are highly accurate...component for an UAV helicopter- magnetometer system is the ability to have precise positioning (both for flightpath execution and for data acquisition...discussed under section 6.3. Figure 6.11 shows the fluxgate data used to compensate a total field magnetometer as previously described. The red

Field Measurement of Surface Ship Magnetic Signature Using Multiple AUVs

DTIC Science & Technology

2009-10-01

been equipped with a tri-axial fluxgate magnetometer and used to perform preliminary magnetic field measurements. Measurements of this type will be...mounted on the AUVs, shown in Fig. 1, was a three-axis fluxgate type [16] magnetometer with a range of ±100,000 nT and a sensitivity of 100μV/nT. The...surface ship. The system will employ a formation of multiple AUVs, each equipped with a magnetometer . The objective is to measure total magnetic

Investigating dynamical complexity in the time series of the upgraded ENIGMA magnetometer array using various entropy measures

NASA Astrophysics Data System (ADS)

Balasis, Georgios; Daglis, Ioannis A.; Papadimitriou, Constantinos; Melis, Nikolaos; Giannakis, Omiros; Kontoes, Charalampos

2016-04-01

The HellENIc GeoMagnetic Array (ENIGMA) is a network of 3 ground-based magnetometer stations in the areas of Trikala, Attiki and Lakonia in Greece that provides measurements for the study of geomagnetic pulsations, resulting from the solar wind - magnetosphere coupling. ENIGMA magnetometer array enables effective remote sensing of geospace dynamics and the study of space weather effects on the ground (i.e., Geomagnetically Induced Currents - GIC). ENIGMA contributes data to SuperMAG, a worldwide collaboration of organizations and national agencies that currently operate more than 300 ground-based magnetometers. ENIGMA is currently extended and upgraded receiving financial support through the national funding KRIPIS project and European Commission's BEYOND project. In particular, the REGPOT project BEYOND is an FP7 project that aims to maintain and expand the existing state-of-the-art interdisciplinary research potential, by Building a Centre of Excellence for Earth Observation based monitoring of Natural Disasters in south-eastern Europe, with a prospect to increase its access range to the wider Mediterranean region through the integrated cooperation with twining organizations. This study explores the applicability and effectiveness of a variety of computable entropy measures to the ENIGMA time series in order to investigate dynamical complexity between pre-storm activity and magnetic storms.

Estimation of electric fields and current from ground-based magnetometer data

NASA Technical Reports Server (NTRS)

Kamide, Y.; Richmond, A. D.

1984-01-01

Recent advances in numerical algorithms for estimating ionospheric electric fields and currents from groundbased magnetometer data are reviewed and evaluated. Tests of the adequacy of one such algorithm in reproducing large-scale patterns of electrodynamic parameters in the high-latitude ionosphere have yielded generally positive results, at least for some simple cases. Some encouraging advances in producing realistic conductivity models, which are a critical input, are pointed out. When the algorithms are applied to extensive data sets, such as the ones from meridian chain magnetometer networks during the IMS, together with refined conductivity models, unique information on instantaneous electric field and current patterns can be obtained. Examples of electric potentials, ionospheric currents, field-aligned currents, and Joule heating distributions derived from ground magnetic data are presented. Possible directions for future improvements are also pointed out.

A Reduced SWAP+C DC Magnetometer for Geomagnetic and Space Physics Research

NASA Astrophysics Data System (ADS)

Moldwin, M.; Ojeda, L.; Rogacki, S.; Pelloni, M.; Regoli, L.

2016-12-01

A new small, low mass, low power consumption, and low cost (reduced SWaP+C or Size, Weight and Power + Cost) magnetometer is being developed for both ground-based and future CubeSat Constellation-class missions. The University of Michigan (UM) magnetometer is based on the PNI Induction magnetometer electronics. PNI 3100 magnetometers have flight heritage on Cubesat Missions (e.g., the UM RAXs mission), but they were used primarily for attitude control. This presentation describes the modifications and performance of the magnetometer and our strategies for continued improvement in performance and its environmental testing. A description of further development of this new magnetometer with regards to its ability to measure geophysical signals up to 10 Hz is also given. Current performance has noise levels of about 1 nT/root Hz at 1 Hz, temperature stability, inherent radiation tolerance, in a 3 x 5 cm package (electronics and sensors), draws 10s of mW and costs a few hundred dollars. We will also present several strategies to reduce the noise by a factor of 5-10 that are currently being pursued.

Correlations between Geomagnetic Disturbances and Field-Aligned Currents during the 22-29 July 2004 Storm Time Interval

NASA Astrophysics Data System (ADS)

Hood, R.; Woodroffe, J. R.; Morley, S.; Aruliah, A. L.

2017-12-01

Using the CHAMP fluxgate magnetometer to calculate field-aligned current (FAC) densities and magnetic latitudes, with SuperMAG ground magnetometers analogously providing ground geomagnetic disturbances (GMD) magnetic perturbations and latitudes, we probe FAC locations and strengths as predictors of GMD locations and strengths. We also study the relationships between solar wind drivers and global magnetospheric activity, and both FACs and GMDs using IMF Bz and the Sym-H index. We present an event study of the 22-29 July 2004 storm time interval, which had particularly large GMDs given its storm intensity. We find no correlation between FAC and GMD magnitudes, perhaps due to CHAMP orbit limitations or ground magnetometer coverage. There is, however, a correlation between IMF Bz and nightside GMD magnitudes, supportive of their generation via tail reconnection. IMF Bz is also correlated with dayside FAC and GMD magnetic latitudes, indicating solar wind as an initial driver. The ring current influence increases during the final storm, with improved correlations between the Sym-H index and both FAC magnetic latitudes and GMD magnitudes. Sym-H index correlations may only be valid for higher intensity storms; a statistical analysis of many storms is needed to verify this.

Dynamical Networks Characterization of Space Weather Events

NASA Astrophysics Data System (ADS)

Orr, L.; Chapman, S. C.; Dods, J.; Gjerloev, J. W.

2017-12-01

Space weather can cause disturbances to satellite systems, impacting navigation technology and telecommunications; it can cause power loss and aviation disruption. A central aspect of the earth's magnetospheric response to space weather events are large scale and rapid changes in ionospheric current patterns. Space weather is highly dynamic and there are still many controversies about how the current system evolves in time. The recent SuperMAG initiative, collates ground-based vector magnetic field time series from over 200 magnetometers with 1-minute temporal resolution. In principle this combined dataset is an ideal candidate for quantification using dynamical networks. Network properties and parameters allow us to characterize the time dynamics of the full spatiotemporal pattern of the ionospheric current system. However, applying network methodologies to physical data presents new challenges. We establish whether a given pair of magnetometers are connected in the network by calculating their canonical cross correlation. The magnetometers are connected if their cross correlation exceeds a threshold. In our physical time series this threshold needs to be both station specific, as it varies with (non-linear) individual station sensitivity and location, and able to vary with season, which affects ground conductivity. Additionally, the earth rotates and therefore the ground stations move significantly on the timescales of geomagnetic disturbances. The magnetometers are non-uniformly spatially distributed. We will present new methodology which addresses these problems and in particular achieves dynamic normalization of the physical time series in order to form the network. Correlated disturbances across the magnetometers capture transient currents. Once the dynamical network has been obtained [1][2] from the full magnetometer data set it can be used to directly identify detailed inferred transient ionospheric current patterns and track their dynamics. We will show our first results that use network properties such as cliques and clustering coefficients to map these highly dynamic changes in ionospheric current patterns.[l] Dods et al, J. Geophys. Res 120, doi:10.1002/2015JA02 (2015). [2] Dods et al, J. Geophys. Res. 122, doi:10.1002/2016JA02 (2017).

Attitude and Trajectory Estimation Using Earth Magnetic Field Data

NASA Technical Reports Server (NTRS)

Deutschmann, Julie; Bar-Itzhack, Itzhack Y.

1996-01-01

The magnetometer has long been a reliable, inexpensive sensor used in spacecraft momentum management and attitude estimation. Recent studies show an increased accuracy potential for magnetometer-only attitude estimation systems. Since the Earth's magnetic field is a function of time and position, and since time is known quite precisely, the differences between the computer and measured magnetic field components, as measured by the magnetometers throughout the entire spacecraft orbit, are a function of both the spacecraft trajectory and attitude errors. Therefore, these errors can be used to estimate both trajectory and attitude. Traditionally, satellite attitude and trajectory have been estimated with completely separate system, using different measurement data. Recently, trajectory estimation for low earth orbit satellites was successfully demonstrated in ground software using only magnetometer data. This work proposes a single augmented extended Kalman Filter to simultaneously and autonomously estimate both spacecraft trajectory and attitude with data from a magnetometer and either dynamically determined rates or gyro-measured body rates.

Simultaneous Traveling Convection Vortex (TCV) Events and Pc 1-2 Wave Bursts at Cusp/Cleft Latitudes observed in Arctic Canada and Svalbard

NASA Astrophysics Data System (ADS)

Posch, J. L.; Witte, A. J.; Engebretson, M. J.; Murr, D.; Lessard, M.; Raita, T.; Singer, H. J.

2010-12-01

Traveling convection vortices (TCVs), which appear in ground magnetometer records at near-cusp latitudes as solitary ~5 mHz pulses, are now known to originate in instabilities in the ion foreshock just upstream of Earth’s bow shock. They can also stimulate compressions or relaxations of the dayside magnetosphere (evident in geosynchronous satellite data). These transient compressions can in turn sharply increase the growth rate of electromagnetic ion cyclotron (EMIC) waves, which also appear in ground records at near-cusp latitudes as bursts of Pc 1-2 pulsations. In this study we have identified simultaneous TCV - Pc 1-2 burst events occurring from 2008 through the first 7 months of 2010 in Eastern Arctic Canada and Svalbard, using a combination of fluxgate magnetometers (MACCS and IMAGE) and search coil magnetometers in each region. Magnetometer observations at GOES 10 and 12, at longitudes near the MACCS sites, are also used to characterize the strength of the magnetic perturbations. There is no direct proportion between the amplitude of TCV and Pc 1-2 wave events in either region, consistent with the highly variable densities and pitch angle distributions of plasma of ring current / plasma sheet energies in the outer dayside magnetosphere.

Observation of relativistic electron loss induced by EMIC waves in the outer radiation belt: Arase and PWING induction magnetometer array collaboration

NASA Astrophysics Data System (ADS)

Kurita, S.; Yoshizumi, M.; Kazuo, S.; Higashio, N.; Mitani, T.; Takashima, T.; Matsuoka, A.; Teramoto, M.; Shinohara, I.

2017-12-01

EMIC waves are generated by temperature anisotropy of energetic ions near the magnetic equator and satellite observations show that the waves tend to be observed on the dusk side and noon side magnetosphere. EMIC waves can propagate from the magnetosphere to the ground and they are observed by ground-based magnetometers as Pc1 pulsation. It has been pointed out that EMIC waves can resonate with relativistic electrons through anomalous cyclotron resonance, and cause strong pitch angle scattering of radiation belt electrons. It has been considered that precipitation loss of relativistic electrons by pitch angle scattering induced by EMIC waves is an important loss mechanism of radiation belt electrons. We report on the observation of relativistic electron loss observed by the Arase satellite on the dawn side magnetosphere during a geomagnetic disturbance, which is likely to be related to an EMIC wave activity. During the event, the EMIC wave activity in conjunction with the relativistic electron loss is identified from observation by the ground-based induction magnetometer array deployed by the PWING project. The magnetometer array observation reveals that EMIC waves are distributed in the wide magnetic local time range from the dusk to midnight sector. It is suggested that drifting relativistic electrons are scattered into the loss cone by the EMIC waves on the dusk to midnight sector before they arrive at the Arase satellite located on the dawn side. We will discuss the impact of loss caused by EMIC wave-induced precipitation loss on the overall flux variation of radiation belt electrons during the geomagnetic disturbance.

Airborne gamma-ray spectrometer and magnetometer survey: Durango Quadrangle (Colorado). Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1979-07-01

Results from the airborne gamma-ray spectrometer and magnetometer survey of Durango Quadrangle in Colorado are presented in the form of radiometric multiple-parameter stacked profiles, histograms, flight path map, and magnetic and ancillary stacked profile data.

Magnetic Signature: Small Arms Testing of Multiple Examples of Same Model Weapons

DTIC Science & Technology

2009-04-01

inside the wooden building, showing a three-axis fluxgate magnetometer , north-south path lines, and instrumentation system...the FVM-400 Vector Fluxgate Magnetometer by Macintyre Electronics Design Associates, Inc. (MEDA) was used and in other cases two DFM100G2 Digital... Fluxgate Magnetometers made by Billingsley Magnetics were used. The majority of the data obtained was done with the latter. The MEDA has a 1 nT

Variations of High-Latitude Geomagnetic Pulsation Frequencies: A Comparison of Time-of-Flight Estimates and IMAGE Magnetometer Observations

NASA Astrophysics Data System (ADS)

Sandhu, J. K.; Yeoman, T. K.; James, M. K.; Rae, I. J.; Fear, R. C.

2018-01-01

The fundamental eigenfrequencies of standing Alfvén waves on closed geomagnetic field lines are estimated for the region spanning 5.9≤L < 9.5 over all MLT (Magnetic Local Time). The T96 magnetic field model and a realistic empirical plasma mass density model are employed using the time-of-flight approximation, refining previous calculations that assumed a relatively simplistic mass density model. An assessment of the implications of using different mass density models in the time-of-flight calculations is presented. The calculated frequencies exhibit dependences on field line footprint magnetic latitude and MLT, which are attributed to both magnetic field configuration and spatial variations in mass density. In order to assess the validity of the time-of-flight calculated frequencies, the estimates are compared to observations of FLR (Field Line Resonance) frequencies. Using IMAGE (International Monitor for Auroral Geomagnetic Effects) ground magnetometer observations obtained between 2001 and 2012, an automated FLR identification method is developed, based on the cross-phase technique. The average FLR frequency is determined, including variations with footprint latitude and MLT, and compared to the time-of-flight analysis. The results show agreement in the latitudinal and local time dependences. Furthermore, with the use of the realistic mass density model in the time-of-flight calculations, closer agreement with the observed FLR frequencies is obtained. The study is limited by the latitudinal coverage of the IMAGE magnetometer array, and future work will aim to extend the ground magnetometer data used to include additional magnetometer arrays.

Simultaneous observations of traveling convection vortices: Ionosphere-thermosphere coupling

NASA Astrophysics Data System (ADS)

Kim, Hyomin; Lessard, Marc R.; Jones, Sarah L.; Lynch, Kristina A.; Fernandes, Philip A.; Aruliah, Anasuya L.; Engebretson, Mark J.; Moen, Jøran I.; Oksavik, Kjellmar; Yahnin, Alexander G.; Yeoman, Timothy K.

2017-05-01

We present simultaneous observations of magnetosphere-ionosphere-thermosphere coupling over Svalbard during a traveling convection vortex (TCV) event. Various spaceborne and ground-based instruments made coordinated measurements, including magnetometers, particle detectors, an all-sky camera, European Incoherent Scatter (EISCAT) Svalbard Radar, Super Dual Auroral Radar Network (SuperDARN), and SCANning Doppler Imager (SCANDI). The instruments recorded TCVs associated with a sudden change in solar wind dynamic pressure. The data display typical features of TCVs including vortical ionospheric convection patterns seen by the ground magnetometers and SuperDARN radars and auroral precipitation near the cusp observed by the all-sky camera. Simultaneously, electron and ion temperature enhancements with corresponding density increase from soft precipitation are also observed by the EISCAT Svalbard Radar. The ground magnetometers also detected electromagnetic ion cyclotron waves at the approximate time of the TCV arrival. This implies that they were generated by a temperature anisotropy resulting from a compression on the dayside magnetosphere. SCANDI data show a divergence in thermospheric winds during the TCVs, presumably due to thermospheric heating associated with the current closure linked to a field-aligned current system generated by the TCVs. We conclude that solar wind pressure impulse-related transient phenomena can affect even the upper atmospheric dynamics via current systems established by a magnetosphere-ionosphere-thermosphere coupling process.

Probabilistic resident space object detection using archival THEMIS fluxgate magnetometer data

NASA Astrophysics Data System (ADS)

Brew, Julian; Holzinger, Marcus J.

2018-05-01

Recent progress in the detection of small space objects, at geosynchronous altitudes, through ground-based optical and radar measurements is demonstrated as a viable method. However, in general, these methods are limited to detection of objects greater than 10 cm. This paper examines the use of magnetometers to detect plausible flyby encounters with charged space objects using a matched filter signal existence binary hypothesis test approach. Relevant data-set processing and reduction of archival fluxgate magnetometer data from the NASA THEMIS mission is discussed in detail. Using the proposed methodology and a false alarm rate of 10%, 285 plausible detections with probability of detection greater than 80% are claimed and several are reviewed in detail.

Understanding the Longitudinal Variability of Equatorial Electrodynamics using integrated Ground- and Space-based Observations

NASA Astrophysics Data System (ADS)

Yizengaw, E.; Moldwin, M.; Zesta, E.

2015-12-01

The currently funded African Meridian B-Field Education and Research (AMBER) magnetometer array comprises more than thirteen magnetometers stationed globally in the vicinity of geomagnetic equator. One of the main objectives of AMBER network is to understand the longitudinal variability of equatorial electrodynamics as function of local time, magnetic activity, and season. While providing complete meridian observation in the region and filling the largest land-based gap in global magnetometer coverage, the AMBER array addresses two fundamental areas of space physics: first, the processes governing electrodynamics of the equatorial ionosphere as a function of latitude (or L-shell), local time, longitude, magnetic activity, and season, and second, ULF pulsation strength at low/mid-latitude regions and its connection with equatorial electrojet and density fluctuation. The global AMBER network can also be used to augment observations from space-based instruments, such us the triplet SWARM mission and the upcoming ICON missions. Thus, in coordination with space-based and other ground-based observations, the AMBER magnetometer network provides a great opportunity to understand the electrodynamics that governs equatorial ionosphere motions. In this paper we present the longitudinal variability of the equatorial electrodynamics using the combination of instruments onboard SWARM and C/NOFS satellites and ground-based AMBER network. Both ground- and pace-based observations show stronger dayside and evening sector equatorial electrodynamics in the American and Asian sectors compared to the African sector. On the other hand, the African sector is home to stronger and year-round ionospheric bubbles/irregularities compared to the American and Asian sectors. This raises the question if the evening sector equatorial electrodynamics (vertical drift), which is believed to be the main cause for the enhancement of Rayleigh-Taylor (RT) instability growth rate, is stronger in the American sector and weaker in the African sector - why are the occurrence and amplitude of equatorial irregularities stronger in the African sector?

Using Radars in Place of Magnetometers: Detection and Properties of Pc3-5 Wave Fields in HF Radar Data

NASA Astrophysics Data System (ADS)

Ponomarenko, P.; Menk, F. W.; Waters, C. L.

2004-12-01

SuperDARN HF radars are usually used to examine HF echoes from field-aligned ionospheric irregularity structures. However, ground scatter is also often recorded. Because the ground scatter signal is reflected from the ionosphere its Doppler shift is a sensitive indicator of ionospheric motions. We have used the TIGER radar, which operates at relatively low latitudes, to examine ground scatter returns with high time resolution. Ground scatter returns are present virtually every day and wave-like Doppler shift features are evident almost each time. Comparison with ground magnetometer data shows that these are the ionospheric signature of downgoing ULF waves. Several different types of wave features have been observed, including very large scale Pc5, harmonics of field line resonances in the Pc3-4 range, and bandlimited Pc4 at night. This paper presents examples and discusses the wave generation and propagation mechanisms. Furthermore, estimates of the ionospheric transfer function over the 10-110 mHz range are compared with results of numerical and analytical modelling.

The Magnetospheric Multiscale Magnetometers

NASA Technical Reports Server (NTRS)

Russell, C. T.; Anderson, B. J.; Baumjohann, W.; Bromund, K. R.; Dearborn, D.; Fischer, D.; Le, G.; Leinweber, H. K.; Leneman, D.; Magnes, W.;

Coalition Warfare Program Presentation to: 2009 EUCOM/AFRICOM Science and Technology Conference

DTIC Science & Technology

2009-06-01

compac an nexpens ve m cro- fluxgate magnetometer for use in multiple COCOMs. To continue T&E with joint services and apply lessons learned to...Partners in EUCOM/AFRICOM FY08 Starts • Advanced Dynamic Magnetometer FY09 Starts • ADNS Coalition Network FY10 New Starts • Clip-on Night Vision...Partner 2008 New Starts Advanced Dynamic Magnetometer for Static and Moving Applications T d l t d i i i US Navy (SPAWAR) Italy, Sweden o eve op a a

The large-scale ionospheric transient current system response to upstream solar wind IMF Bz north-south and south-north turnings as seen by the WIND satellite and the full SuperMAG network of ground based magnetometers

NASA Astrophysics Data System (ADS)

Dods, Joe; Chapman, Sandra; Gjerloev, Jesper

2017-04-01

We characterise the response of the quiet-time (no substorms or storms) large scale ionospheric convection system to north-south and south-north IMF turnings by using a dynamical network of ground-based magnetometers. Canonical correlation between all pairs of SuperMAG magnetometer stations in the northern hemisphere (MLat 50-82°) is used to establish the extent of near-simultaneous magnetic response between regions of MLT-MLat. Parameters and maps that describe spatial-temporal correlation are used to characterise the system and its response to the turnings aggregated over several hundred events. We find that regions that experience large increases in correlation post-turning coincide with typical locations of a two cell convection system and are influenced by the IMF By. The time between the turnings reaching the magnetopause and a network response is found to be ˜8-10 minutes and correlation in the dayside occurs 2-8 mins before that in the nightside.

First radar observations in the vicinity of the plasmapause of pulsed ionospheric flows generated by bursty bulk flows

NASA Astrophysics Data System (ADS)

Frissell, N. A.; Baker, J. B. H.; Ruohoniemi, J. M.; Clausen, L. B. N.; Kale, Z. C.; Rae, I. J.; Kepko, L.; Oksavik, K.; Greenwald, R. A.; West, M. L.

2011-01-01

Recent expansion of the SuperDARN network to mid-latitudes and the addition of a new high-time resolution mode provides new opportunities to observe mid-latitude ultra-low frequency waves and other ionospheric sub-auroral features at high temporal resolution. On 22 February 2008, the Blackstone SuperDARN radar and THEMIS ground magnetometers simultaneously observed substorm Pi2 pulsations. Similarities in measurements from the Blackstone radar and a magnetometer at Remus suggest a common generating mechanism. Cross-phase analysis of magnetometer data places these measurements at the ionospheric projection of the plasmapause, while fine spatial and temporal details of the radar data show evidence of field line compressions. About 1 min prior to ground Pi2 observation, 2 Earthward-moving Bursty Bulk Flows (BBFs) were observed by THEMIS probes D and E in the near-Earth plasma sheet. We conclude that the first 2 pulses of the Pi2s observed at Blackstone and Remus result from compressional energy generated by BBFs braking against the magnetospheric dipolar region.

Quantum critical environment assisted quantum magnetometer

NASA Astrophysics Data System (ADS)

Jaseem, Noufal; Omkar, S.; Shaji, Anil

2018-04-01

A central qubit coupled to an Ising ring of N qubits, operating close to a critical point is investigated as a potential precision quantum magnetometer for estimating an applied transverse magnetic field. We compute the quantum Fisher information for the central, probe qubit with the Ising chain initialized in its ground state or in a thermal state. The non-unitary evolution of the central qubit due to its interaction with the surrounding Ising ring enhances the accuracy of the magnetic field measurement. Near the critical point of the ring, Heisenberg-like scaling of the precision in estimating the magnetic field is obtained when the ring is initialized in its ground state. However, for finite temperatures, the Heisenberg scaling is limited to lower ranges of N values.

Evolution of the current system during solar wind pressure pulses based on aurora and magnetometer observations

NASA Astrophysics Data System (ADS)

Nishimura, Yukitoshi; Kikuchi, Takashi; Ebihara, Yusuke; Yoshikawa, Akimasa; Imajo, Shun; Li, Wen; Utada, Hisashi

2016-08-01

We investigated evolution of ionospheric currents during sudden commencements using a ground magnetometer network in conjunction with an all-sky imager, which has the advantage of locating field-aligned currents much more accurately than ground magnetometers. Preliminary (PI) and main (MI) impulse currents showed two-cell patterns propagating antisunward, particularly during a southward interplanetary magnetic field (IMF). Although this overall pattern is consistent with the Araki (solar wind sources of magnetospheric ultra-low-frequency waves. Geophysical monograph series, vol 81. AGU, Washington, DC, pp 183-200, 1994. doi: 10.1029/GM081p0183) model, we found several interesting features. The PI and MI currents in some events were highly asymmetric with respect to the noon-midnight meridian; the post-noon sector did not show any notable PI signal, but only had an MI starting earlier than the pre-noon MI. Not only equivalent currents but also aurora and equatorial magnetometer data supported the much weaker PI response. We suggest that interplanetary shocks impacting away from the subsolar point caused the asymmetric current pattern. Additionally, even when PI currents form in both pre- and post-noon sectors, they can initiate and disappear at different timings. The PI currents did not immediately disappear but coexisted with the MI currents for the first few minutes of the MI. During a southward IMF, the MI currents formed equatorward of a preexisting DP-2, indicating that the MI currents are a separate structure from a preexisting DP-2. In contrast, the MI currents under a northward IMF were essentially an intensification of a preexisting DP-2. The magnetometer and imager combination has been shown to be a powerful means for tracing evolution of ionospheric currents, and we showed various types of ionospheric responses under different upstream conditions.

ESTCP UXO Discrimination Study. MTADS Demonstration at Camp Sibert Magnetometer / EM61 MkII / GEM-3 Arrays, Gadsden, AL, April 2007

DTIC Science & Technology

2008-08-21

Yuma Proving Ground Open Field ............................................................................... 76 B.3.1 Response Stage... Yuma Proving Ground ZIP (250) Iomega ZIP disk (250 MB version) xv ACKNOWLEDGEMENTS Glenn Harbaugh and Daniel Steinhurst (P.I.) of Nova Research...sites at Aberdeen Proving Ground and Yuma Proving Ground in 2003 and 2004 [6]. At each of the sites, the Calibration Lanes, the Blind Test Grid

Demonstration of Airborne Electromagnetic Systems for Detection and Characterization of Unexploded Ordnance at the Badlands Bombing Range, South Dakota. Revision 3

DTIC Science & Technology

2004-08-01

base station Attitude Measurement Ashtech ADU-2 Bartington MAG03ML7ONT 3-axis fluxgate magnetometer , Navigation Picodas PNAV100 Model P141-E Real...BBR Test Grid, horizontal difference (outer coil minus scaled inner coil). 46 22 Analytic signal derived from ground-based magnetometer bottom...one meter over UXO-contaminated terrain. As with the magnetic systems, GPS and laser altimetry provide precise positioning to within a few tens of

Simultaneous observations of traveling convection vortices: Ionosphere-thermosphere coupling: M-I-T COUPLING OF TCV

DOE PAGES

Kim, Hyomin; Lessard, Marc R.; Jones, Sarah L.; ...

2017-03-11

We present simultaneous observations of magnetosphere-ionosphere-thermosphere coupling over Svalbard during a traveling convection vortex (TCV) event. Various spaceborne and ground-based instruments made coordinated measurements, including magnetometers, particle detectors, an all-sky camera, European Incoherent Scatter (EISCAT) Svalbard Radar, Super Dual Auroral Radar Network (SuperDARN), and SCANning Doppler Imager (SCANDI). The instruments recorded TCVs associated with a sudden change in solar wind dynamic pressure. The data display typical features of TCVs including vortical ionospheric convection patterns seen by the ground magnetometers and SuperDARN radars and auroral precipitation near the cusp observed by the all-sky camera. Simultaneously, electron and ion temperature enhancements withmore » corresponding density increase from soft precipitation are also observed by the EISCAT Svalbard Radar. The ground magnetometers also detected electromagnetic ion cyclotron waves at the approximate time of the TCV arrival. This implies that they were generated by a temperature anisotropy resulting from a compression on the dayside magnetosphere. SCANDI data show a divergence in thermospheric winds during the TCVs, presumably due to thermospheric heating associated with the current closure linked to a field-aligned current system generated by the TCVs. We conclude that solar wind pressure impulse-related transient phenomena can affect even the upper atmospheric dynamics via current systems established by a magnetosphere-ionosphere-thermosphere coupling process.« less

Simultaneous observations of traveling convection vortices: Ionosphere-thermosphere coupling: M-I-T COUPLING OF TCV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Hyomin; Lessard, Marc R.; Jones, Sarah L.

We present simultaneous observations of magnetosphere-ionosphere-thermosphere coupling over Svalbard during a traveling convection vortex (TCV) event. Various spaceborne and ground-based instruments made coordinated measurements, including magnetometers, particle detectors, an all-sky camera, European Incoherent Scatter (EISCAT) Svalbard Radar, Super Dual Auroral Radar Network (SuperDARN), and SCANning Doppler Imager (SCANDI). The instruments recorded TCVs associated with a sudden change in solar wind dynamic pressure. The data display typical features of TCVs including vortical ionospheric convection patterns seen by the ground magnetometers and SuperDARN radars and auroral precipitation near the cusp observed by the all-sky camera. Simultaneously, electron and ion temperature enhancements withmore » corresponding density increase from soft precipitation are also observed by the EISCAT Svalbard Radar. The ground magnetometers also detected electromagnetic ion cyclotron waves at the approximate time of the TCV arrival. This implies that they were generated by a temperature anisotropy resulting from a compression on the dayside magnetosphere. SCANDI data show a divergence in thermospheric winds during the TCVs, presumably due to thermospheric heating associated with the current closure linked to a field-aligned current system generated by the TCVs. We conclude that solar wind pressure impulse-related transient phenomena can affect even the upper atmospheric dynamics via current systems established by a magnetosphere-ionosphere-thermosphere coupling process.« less

The THEMIS Array of Ground-based Observatories for the Study of Auroral Substorms

NASA Astrophysics Data System (ADS)

Mende, S. B.; Harris, S. E.; Frey, H. U.; Angelopoulos, V.; Russell, C. T.; Donovan, E.; Jackel, B.; Greffen, M.; Peticolas, L. M.

2008-12-01

The NASA Time History of Events and Macroscale Interactions during Substorms (THEMIS) project is intended to investigate magnetospheric substorm phenomena, which are the manifestations of a basic instability of the magnetosphere and a dominant mechanism of plasma transport and explosive energy release. The major controversy in substorm science is the uncertainty as to whether the instability is initiated near the Earth, or in the more distant >20 Re magnetic tail. THEMIS will discriminate between the two possibilities by using five in-situ satellites and ground-based all-sky imagers and magnetometers, and inferring the propagation direction by timing the observation of the substorm initiation at multiple locations in the magnetosphere. An array of stations, consisting of 20 all-sky imagers (ASIs) and 30-plus magnetometers, has been developed and deployed in the North American continent, from Alaska to Labrador, for the broad coverage of the nightside magnetosphere. Each ground-based observatory (GBO) contains a white light imager that takes auroral images at a 3-second repetition rate (“cadence”) and a magnetometer that records the 3 axis variation of the magnetic field at 2 Hz frequency. The stations return compressed images, “thumbnails,” to two central databases: one located at UC Berkeley and the other at the University of Calgary, Canada. The full images are recorded at each station on hard drives, and these devices are physically returned to the two data centers for data copying. All data are made available for public use by scientists in “browse products,” accessible by using internet browsers or in the form of downloadable CDF data files (the “browse products” are described in detail in a later section). Twenty all-sky imager stations are installed and running at the time of this publication. An example of a substorm was observed on the 23rd of December 2006, and from the THEMIS GBO data, we found that the substorm onset brightening of the equatorward arc was a gradual process (>27 seconds), with minimal morphology changes until the arc breaks up. The breakup was timed to the nearest frame (<3 s) and located to the nearest latitude degree at about ±3oE in longitude. The data also showed that a similar breakup occurred in Alaska ˜10 minutes later, highlighting the need for an array to distinguish prime onset.

Cluster spacecraft observations of a ULF wave enhanced by Space Plasma Exploration by Active Radar (SPEAR)

NASA Astrophysics Data System (ADS)

Badman, S. V.; Wright, D. M.; Clausen, L. B. N.; Fear, R. C.; Robinson, T. R.; Yeoman, T. K.

2009-09-01

Space Plasma Exploration by Active Radar (SPEAR) is a high-latitude ionospheric heating facility capable of exciting ULF waves on local magnetic field lines. We examine an interval from 1 February 2006 when SPEAR was transmitting a 1 Hz modulation signal with a 10 min on-off cycle. Ground magnetometer data indicated that SPEAR modulated currents in the local ionosphere at 1 Hz, and enhanced a natural field line resonance with a 10 min period. During this interval the Cluster spacecraft passed over the heater site. Signatures of the SPEAR-enhanced field line resonance were present in the magnetic field data measured by the magnetometer on-board Cluster-2. These are the first joint ground- and space-based detections of field line tagging by SPEAR.

Ionospheric and Birkeland current distributions inferred from the MAGSAT magnetometer data

NASA Technical Reports Server (NTRS)

Zanetti, L. J.; Potemra, T. A.; Baumjohann, W.

1983-01-01

Ionospheric and field-aligned sheet current density distributions are presently inferred by means of MAGSAT vector magnetometer data, together with an accurate magnetic field model. By comparing Hall current densities inferred from the MAGSAT data and those inferred from simultaneously recorded ground based data acquired by the Scandinavian magnetometer array, it is determined that the former have previously been underestimated due to high damping of magnetic variations with high spatial wave numbers between the ionosphere and the MAGSAT orbit. Among important results of this study is noted the fact that the Birkeland and electrojet current systems are colocated. The analyses have shown a tendency for triangular rather than constant electrojet current distributions as a function of latitude, consistent with the statistical, uniform regions 1 and 2 Birkeland current patterns.

Remote sensing the plasmasphere, plasmapause, plumes and other features using ground-based magnetometers

NASA Astrophysics Data System (ADS)

Menk, Frederick; Kale, Zoë; Sciffer, Murray; Robinson, Peter; Waters, Colin; Grew, Russell; Clilverd, Mark; Mann, Ian

2014-11-01

The plasmapause is a highly dynamic boundary between different magnetospheric particle populations and convection regimes. Some of the most important space weather processes involve wave-particle interactions in this region, but wave properties may also be used to remote sense the plasmasphere and plasmapause, contributing to plasmasphere models. This paper discusses the use of existing ground magnetometer arrays for such remote sensing. Using case studies we illustrate measurement of plasmapause location, shape and movement during storms; refilling of flux tubes within and outside the plasmasphere; storm-time increase in heavy ion concentration near the plasmapause; and detection and mapping of density irregularities near the plasmapause, including drainage plumes, biteouts and bulges. We also use a 2D MHD model of wave propagation through the magnetosphere, incorporating a realistic ionosphere boundary and Alfvén speed profile, to simulate ground array observations of power and cross-phase spectra, hence confirming the signatures of plumes and other density structures.

Nowcasting Ground Magnetic Perturbations with the Space Weather Modeling Framework

NASA Astrophysics Data System (ADS)

Welling, D. T.; Toth, G.; Singer, H. J.; Millward, G. H.; Gombosi, T. I.

2015-12-01

Predicting ground-based magnetic perturbations is a critical step towards specifying and predicting geomagnetically induced currents (GICs) in high voltage transmission lines. Currently, the Space Weather Modeling Framework (SWMF), a flexible modeling framework for simulating the multi-scale space environment, is being transitioned from research to operational use (R2O) by NOAA's Space Weather Prediction Center. Upon completion of this transition, the SWMF will provide localized B/t predictions using real-time solar wind observations from L1 and the F10.7 proxy for EUV as model input. This presentation describes the operational SWMF setup and summarizes the changes made to the code to enable R2O progress. The framework's algorithm for calculating ground-based magnetometer observations will be reviewed. Metrics from data-model comparisons will be reviewed to illustrate predictive capabilities. Early data products, such as regional-K index and grids of virtual magnetometer stations, will be presented. Finally, early successes will be shared, including the code's ability to reproduce the recent March 2015 St. Patrick's Day Storm.

Iterative Magnetometer Calibration

NASA Technical Reports Server (NTRS)

Sedlak, Joseph

2006-01-01

This paper presents an iterative method for three-axis magnetometer (TAM) calibration that makes use of three existing utilities recently incorporated into the attitude ground support system used at NASA's Goddard Space Flight Center. The method combines attitude-independent and attitude-dependent calibration algorithms with a new spinning spacecraft Kalman filter to solve for biases, scale factors, nonorthogonal corrections to the alignment, and the orthogonal sensor alignment. The method is particularly well-suited to spin-stabilized spacecraft, but may also be useful for three-axis stabilized missions given sufficient data to provide observability.

Comparison of DMSP and SECS region-1 and region-2 ionospheric current boundary

NASA Astrophysics Data System (ADS)

Weygand, J. M.; Wing, S.

2016-06-01

The region-1 and region-2 boundary has traditionally been identified using data from a single spacecraft crossing the auroral region and measuring the large scale changes in the cross track magnetic field. With data from the AUTUMN, CANMOS, CARISMA, GIMA, DTU MGS, MACCS, McMAC, STEP, THEMIS, and USGS ground magnetometer arrays we applied a state-of-art technique based on spherical elementary current system (SECS) method developed by Amm and Viljanen (1999) in order to calculate maps of region-1 and region-2 current system over the North American and Greenland auroral region. Spherical elementary current (SEC) amplitude (proxy for vertical currents) maps can be inferred at 10 s temporal resolution, ~1.5° geographic latitude (Glat), and 3.5° geographic longitude (Glon) spatial resolution. We compare the location of the region-1 and region-2 boundary obtained by the DMSP spacecraft with the region-1 and region-2 boundary observed in the SEC current amplitudes. We find that the boundaries typically agree within 0.2°±1.3°. These results indicate that the location of the region-1 and region-2 boundary can reasonably be determined from ground magnetometer data. The SECS maps represent a value-added product from the magnetometer database and can be used for contextual interpretation in conjunction with other missions as well as help with our understanding of magnetosphere-ionosphere coupling mechanisms using the ground arrays and the magnetospheric spacecraft data.

Comparison of DMSP and SECS region-1 and region-2 ionospheric current boundary✩

PubMed Central

Weygand, J.M.; Wing, S.

2017-01-01

The region-1 and region-2 boundary has traditionally been identified using data from a single spacecraft crossing the auroral region and measuring the large scale changes in the cross track magnetic field. With data from the AUTUMN, CANMOS, CARISMA, GIMA, DTU MGS, MACCS, McMAC, STEP, THEMIS, and USGS ground magnetometer arrays we applied a state-of-art technique based on spherical elementary current system (SECS) method developed by Amm and Viljanen (1999) in order to calculate maps of region-1 and region-2 current system over the North American and Greenland auroral region. Spherical elementary current (SEC) amplitude (proxy for vertical currents) maps can be inferred at 10 s temporal resolution, ~1.5° geographic latitude (Glat), and 3.5° geographic longitude (Glon) spatial resolution. We compare the location of the region-1 and region-2 boundary obtained by the DMSP spacecraft with the region-1 and region-2 boundary observed in the SEC current amplitudes. We find that the boundaries typically agree within 0.2° ± 1.3°. These results indicate that the location of the region-1 and region-2 boundary can reasonably be determined from ground magnetometer data. The SECS maps represent a value-added product from the magnetometer database and can be used for contextual interpretation in conjunction with other missions as well as help with our understanding of magnetosphere-ionosphere coupling mechanisms using the ground arrays and the magnetospheric spacecraft data. PMID:29056861

Comparison of DMSP and SECS region-1 and region-2 ionospheric current boundary.

PubMed

Weygand, J M; Wing, S

2016-06-01

The region-1 and region-2 boundary has traditionally been identified using data from a single spacecraft crossing the auroral region and measuring the large scale changes in the cross track magnetic field. With data from the AUTUMN, CANMOS, CARISMA, GIMA, DTU MGS, MACCS, McMAC, STEP, THEMIS, and USGS ground magnetometer arrays we applied a state-of-art technique based on spherical elementary current system (SECS) method developed by Amm and Viljanen (1999) in order to calculate maps of region-1 and region-2 current system over the North American and Greenland auroral region. Spherical elementary current (SEC) amplitude (proxy for vertical currents) maps can be inferred at 10 s temporal resolution, ~1.5° geographic latitude (Glat), and 3.5° geographic longitude (Glon) spatial resolution. We compare the location of the region-1 and region-2 boundary obtained by the DMSP spacecraft with the region-1 and region-2 boundary observed in the SEC current amplitudes. We find that the boundaries typically agree within 0.2° ± 1.3°. These results indicate that the location of the region-1 and region-2 boundary can reasonably be determined from ground magnetometer data. The SECS maps represent a value-added product from the magnetometer database and can be used for contextual interpretation in conjunction with other missions as well as help with our understanding of magnetosphere-ionosphere coupling mechanisms using the ground arrays and the magnetospheric spacecraft data.

Fluxgate Magnetometer system mounted on UAS system: First field test at Dominga IOCG deposit, Chile

NASA Astrophysics Data System (ADS)

Yanez, G. A.; Banchero, L.; Marco, A.; Figueroa, R.

2016-12-01

With the support of Fundacion Chile (FCH) grant, we developed an airborne magnetic system (GeoMagDrone GFDAS) mounted on a UAS octodrone platform (DJI, S1000), based on a low cost/light-weight fluxgate magnetometer (FGM-301) and a robust/light-weight data logger for position, temperature, radar altimeter and 3 magnetic components at 16 Hz recording. Fluxgate magnetometer is hanging from the UAS platform at a distance of 2.5m where the EM noise is reduced to less than 2 nT. The whole geophysical system, including batteries, weights 650 gr., with an autonomy of 2 hours. Magnetometer calibration includes the 9 coefficients of amplitude, offset, and orthogonality, and temperature correction. We test the system over the IOCG deposit of Dominga-Chile, a magnetite ore (40%) (a block of 2x3 km with NS lines separated every 50m and a clearance of 40m, the mineral deposit buried 50-100m from the surface, where a ground magnetic survey was conducted previously. Ground conditions includes relatively rough topography with slopes of 10-20%, and some windy days. We use the digital terrain model SRTM30 to define the drape flight shape Average flight performance includes a mean speed of 35-40 km/hour, and an UAS battery consumption of 18-12 minutes depending on the wind conditions. A good correspondence was found between plan deployment and survey results in terms of line direction/separation/clearance. Line path were flown with errors less than 5 meters, whereas clearance of 40m was kept depending on the amount of control points used. The comparison between ground survey and GeoMagDrone results show a perfect match (anomaly amplitude/shape and noise envelope), validating in this way the system developed. Main concern for the productive application of this technology in unmanned geophysical platforms is the battery performance and the quality of digital terrain models to follow the topography.

Ground magnetometer survey in the Valley of Ten Thousand Smokes, Alaska. M.S. Thesis

NASA Technical Reports Server (NTRS)

Trible, M. C.

1972-01-01

A reconnaissance magnetometer survey was conducted with both total- and vertical-field magnetometers. The large, sharp, narrow total magnetic anomalies observed over a zone of relict fumaroles in Broken Mountain Valley showed spectacular agreement with the surficial geology. Such a correlation is a strong indication that accumulations of magnetic minerals have been preserved along these fissure vents at shallow depths. Since large magnetic anomalies were measured near fumarolic markings along all of the traverses, it is proposed that the retention of sublimates along fumarolic vents is common throughout the Valley. The generally concentric contours of the vertical magnetic anomaly at the head of the Valley suggest that the dome of Novarupta is merely the surficial expression of a very massive conical-shaped intrusive centered just northeast of the dome. The magnetometer survey indicates that the pyroclastics in the Valley may be over 150 meters thick. Such an estimate is compatible with the volume of eruptive material needed to compensate for the subsidence surrounding Novarupta as well as a sizable amount of other regional subsidence.

netPICOmag: from Design to Network Implementation

NASA Astrophysics Data System (ADS)

Schofield, I.; Connors, M.; Russell, C.

2009-05-01

netPICOmag is the successful conclusion of a design effort involving networking based on Rabbit microcontrollers, PIC microcontrollers, and pulsed magnetometer sensors. GPS timing allows both timestamping of data and the precision counting of the number of pulses produced by the sensor heads in one second. Power over Ethernet, use of DHCP, and broadcast of UDP packets mean a very simple local installation, with one wire leading to a relatively small integrated sensor package which is vertically placed in the ground. Although we continue to make improvements, including through investigating new sensor types, we regard the design as mature and well tested. Here we focus on the need for yet denser magnetometer networks, technological applications which become practical using sensitive yet inexpensive magnetometers, and deployment methods for large numbers of sensors. With careful calibration, netPICOmags overlap with research grade magnetometers. Without it, they still sensitively detect magnetic variations and can be used for an education or outreach program. Due to their low cost, such an application allows many students to be directly involved in gathering data that can be very relevant to them personally when they witness auroras.

Synchronous optical pumping of quantum revival beats for atomic magnetometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seltzer, S. J.; Meares, P. J.; Romalis, M. V.

2007-05-15

We observe quantum beats with periodic revivals due to nonlinear spacing of Zeeman levels in the ground state of potassium atoms, and demonstrate their synchronous optical pumping by double modulation of the pumping light at the Larmor frequency and the revival frequency. We show that synchronous pumping increases the degree of spin polarization by a factor of 4. As a practical example, we explore the application of this double-modulation technique to atomic magnetometers operating in the geomagnetic field range, and find that it can increase the sensitivity and reduce magnetic-field-orientation-dependent measurement errors endemic to alkali-metal magnetometers.

Evaluating detection and estimation capabilities of magnetometer-based vehicle sensors

NASA Astrophysics Data System (ADS)

Slater, David M.; Jacyna, Garry M.

2013-05-01

In an effort to secure the northern and southern United States borders, MITRE has been tasked with developing Modeling and Simulation (M&S) tools that accurately capture the mapping between algorithm-level Measures of Performance (MOP) and system-level Measures of Effectiveness (MOE) for current/future surveillance systems deployed by the the Customs and Border Protection Office of Technology Innovations and Acquisitions (OTIA). This analysis is part of a larger M&S undertaking. The focus is on two MOPs for magnetometer-based Unattended Ground Sensors (UGS). UGS are placed near roads to detect passing vehicles and estimate properties of the vehicle's trajectory such as bearing and speed. The first MOP considered is the probability of detection. We derive probabilities of detection for a network of sensors over an arbitrary number of observation periods and explore how the probability of detection changes when multiple sensors are employed. The performance of UGS is also evaluated based on the level of variance in the estimation of trajectory parameters. We derive the Cramer-Rao bounds for the variances of the estimated parameters in two cases: when no a priori information is known and when the parameters are assumed to be Gaussian with known variances. Sample results show that UGS perform significantly better in the latter case.

Short-term Forecasting Ground Magnetic Perturbations with the Space Weather Modeling Framework

NASA Astrophysics Data System (ADS)

Welling, Daniel; Toth, Gabor; Gombosi, Tamas; Singer, Howard; Millward, George

2016-04-01

Predicting ground-based magnetic perturbations is a critical step towards specifying and predicting geomagnetically induced currents (GICs) in high voltage transmission lines. Currently, the Space Weather Modeling Framework (SWMF), a flexible modeling framework for simulating the multi-scale space environment, is being transitioned from research to operational use (R2O) by NOAA's Space Weather Prediction Center. Upon completion of this transition, the SWMF will provide localized dB/dt predictions using real-time solar wind observations from L1 and the F10.7 proxy for EUV as model input. This presentation describes the operational SWMF setup and summarizes the changes made to the code to enable R2O progress. The framework's algorithm for calculating ground-based magnetometer observations will be reviewed. Metrics from data-model comparisons will be reviewed to illustrate predictive capabilities. Early data products, such as regional-K index and grids of virtual magnetometer stations, will be presented. Finally, early successes will be shared, including the code's ability to reproduce the recent March 2015 St. Patrick's Day Storm.

NONDESTRUCTIVE TESTING (NDT) TECHNIQUES TO DETECT CONTAINED SUBSURFACE HAZARDOUS WASTE

EPA Science Inventory

The project involves the detection of buried containers with NDT (remote-sensing) techniques. Seventeen techniques were considered and four were ultimately decided upon. They were: electromagnetic induction (EMI); metal detection (MD); magnetometer (MAG); and ground penetrating r...

Dynamical Networks Characterization of Geomagnetic Substorms and Transient Response to the Solar Wind State.

NASA Astrophysics Data System (ADS)

Chapman, S. C.; Dods, J.; Gjerloev, J. W.

2017-12-01

Observations of how the solar wind interacts with earth's magnetosphere, and its dynamical response, are increasingly becoming a data analytics challenge. Constellations of satellites observe the solar corona, the upstream solar wind and throughout earth's magnetosphere. These data are multipoint in space and extended in time, so in principle are ideal for study using dynamical networks to characterize the full time evolving spatial pattern. We focus here on analysis of data from the full set of 100+ auroral ground based magnetometer stations that have been collated by SuperMAG. Spatio-temporal patterns of correlation between the magnetometer time series can be used to form a dynamical network [1]. The properties of the network can then be captured by (time dependent) network parameters. This offers the possibility of characterizing detailed spatio-temporal pattern by a few parameters, so that many events can then be compared [2] with each other. Whilst networks are in widespread use in the data analytics of societal and commercial data, there are additional challenges in their application to physical timeseries. Determining whether two nodes (here, ground based magnetometer stations) are connected in a network (seeing the same dynamics) requires normalization w.r.t. the detailed sensitivities and dynamical responses of specific observing stations and seasonal conductivity variations and we have developed methods to achieve this dynamical normalization. The detailed properties of the network capture time dependent spatial correlation in the magnetometer responses and we will show how this can be used to infer a transient current system response to magnetospheric activity. [l] Dods et al, J. Geophys. Res 120, doi:10.1002/2015JA02 (2015). [2] Dods et al, J. Geophys. Res. 122, doi:10.1002/2016JA02 (2017).

In-Flight Calibration Processes for the MMS Fluxgate Magnetometers

NASA Astrophysics Data System (ADS)

Bromund, K. R.; Leinweber, H. K.; Plaschke, F.; Strangeway, R. J.; Magnes, W.; Fischer, D.; Nakamura, R.; Anderson, B. J.; Russell, C. T.; Baumjohann, W.; Chutter, M.; Torbert, R. B.; Le, G.; Slavin, J. A.; Kepko, L.

2015-12-01

The calibration effort for the Magnetospheric Multiscale Mission (MMS) Analog Fluxgate (AFG) and Digital Fluxgate (DFG) magnetometers is a coordinated effort between three primary institutions: University of California, Los Angeles (UCLA); Space Research Institute, Graz, Austria (IWF); and Goddard Space Flight Center (GSFC). Since the successful deployment of all 8 magnetometers on 17 March 2015, the effort to confirm and update the ground calibrations has been underway during the MMS commissioning phase. The in-flight calibration processes evaluate twelve parameters that determine the alignment, orthogonalization, offsets, and gains for all 8 magnetometers using algorithms originally developed by UCLA and the Technical University of Braunschweig and tailored to MMS by IWF, UCLA, and GSFC. We focus on the processes run at GSFC to determine the eight parameters associated with spin tones and harmonics. We will also discuss the processing flow and interchange of parameters between GSFC, IWF, and UCLA. IWF determines the low range spin axis offsets using the Electron Drift Instrument (EDI). UCLA determines the absolute gains and sensor azimuth orientation using Earth field comparisons. We evaluate the performance achieved for MMS and give examples of the quality of the resulting calibrations.

Analysis of magnetometer data/wave signals in the Earth's magnetosphere

NASA Technical Reports Server (NTRS)

Engebretson, Mark J.

1993-01-01

Work on the reduction and analysis of Dynamics Explorer (DE) satellite magnetometer data with special emphasis on the ULF fluctuations and waves evident in such data is described. Research focused on the following: (1) studies of Pc 1 wave packets near the plasmapause; (2) satellite-ground pulsation study; (3) support for studies of ion energization processes; (4) search for Pc 1 wave events in 1981 DE 1 data; (5) study of Pc 3-5 events observed simultaneously by DE 1 and by AMPTE CCE; (6) support for studies of electromagnetic transients on DE 1; and (7) analysis of wave events induced by sudden impulses.

MMS, Van Allen Probes, and Ground-based Magnetometer Observations of a Compression-induced EMIC Wave Event

NASA Astrophysics Data System (ADS)

Capman, N.; Engebretson, M.; Posch, J. L.; Cattell, C. A.; Tian, S.; Wygant, J. R.; Kletzing, C.; Lessard, M.; Anderson, B. J.; Russell, C. T.; Reeves, G. D.; Fuselier, S. A.

2016-12-01

A 0.5-1.0 Hz electromagnetic ion cyclotron (EMIC) wave event was observed on December 14, 2015 from 13:26 to 13:28 UT at the four MMS satellites (L= 9.5, MLT= 13.0, MLAT= -24.4, peak amplitude 7 nT), and both Van Allen probes (RBSP-A: L= 5.7, MLT= 12.8, MLAT= 19.5, peak amplitude 5 nT; RBSP-B: L= 4.3, MLT= 14.2, MLAT= 11.3, peak amplitude 1 nT). On the ground, it was observed by search coil magnetometers at Halley Bay and South Pole, Antarctica, and Sondrestromfjord, Greenland, and by fluxgate magnetometers of the MACCS array at Pangnirtung and Cape Dorset in Arctic Canada. This event was preceded by a small increase of the solar wind pressure of 3 nPa from 13:10 to 13:20 UT. The proton distributions at Van Allen probe A confirm that the compression increased the pitch angle anisotropy in 10 keV ring current protons. The wave forms were very similar at the four MMS spacecraft indicating that the coherence-scale of the wave packets is larger than the inter-spacecraft separations of 20 km at the time. Inter-comparison of the wave signals at the four MMS spacecraft are used to assess the characteristics of the waves and estimate their spatial scales transverse and parallel to the background magnetic field.

UAV magnetometry in mineral exploration and infrastructure detection

NASA Astrophysics Data System (ADS)

Braun, A.; Parvar, K.; Burns, M.

2015-12-01

Magnetic surveys are critical tools in mineral exploration and UAVs have the potential to carry magnetometers. UAV surveys can offer higher spatial resolution than traditional airborne surveys, and higher coverage than terrestrial surveys. However, the main advantage is their ability to sense the magnetic field in 3-D, while most airborne or terrestrial surveys are restricted to 2-D acquisition. This study compares UAV magnetic data from two different UAVs (JIB drone, DJI Phantom 2) and three different magnetometers (GEM GSPM35, Honeywell HMR2300, GEM GST-19). The first UAV survey was conducted using a JIB UAV with a GSPM35 flying at 10-15 m above ground. The survey's goal was to detect intrusive Rhyolite bodies for primary mineral exploration. The survey resulted in a better understanding of the validity/resolution of UAV data and led to improved knowledge about the geological structures in the area. The results further drove the design of a following terrestrial survey. Comparing the UAV data with an available airborne survey (upward continued to 250 m) reveals that the UAV data has superior spatial resolution, but exhibits a higher noise level. The magnetic anomalies related to the Rhyolite intrusions is about 109 nT and translates into an estimated depth of approximately 110 meters. The second survey was conducted using an in-house developed UAV magnetometer system equipped with a DJI Phantom 2 and a Honeywell HMR2300 fluxgate magnetometer. By flying the sensor in different altitudes, the vertical and horizontal gradients can be derived leading to full 3-D magnetic data volumes which can provide improved constraints for source depth/geometry characterization. We demonstrate that a buried steam pipeline was detectable with the UAV magnetometer system and compare the resulting data with a terrestrial survey using a GEM GST-19 Proton Precession Magnetometer.

A spinner magnetometer for large Apollo lunar samples.

PubMed

Uehara, M; Gattacceca, J; Quesnel, Y; Lepaulard, C; Lima, E A; Manfredi, M; Rochette, P

2017-10-01

We developed a spinner magnetometer to measure the natural remanent magnetization of large Apollo lunar rocks in the storage vault of the Lunar Sample Laboratory Facility (LSLF) of NASA. The magnetometer mainly consists of a commercially available three-axial fluxgate sensor and a hand-rotating sample table with an optical encoder recording the rotation angles. The distance between the sample and the sensor is adjustable according to the sample size and magnetization intensity. The sensor and the sample are placed in a two-layer mu-metal shield to measure the sample natural remanent magnetization. The magnetic signals are acquired together with the rotation angle to obtain stacking of the measured signals over multiple revolutions. The developed magnetometer has a sensitivity of 5 × 10 -7 Am 2 at the standard sensor-to-sample distance of 15 cm. This sensitivity is sufficient to measure the natural remanent magnetization of almost all the lunar basalt and breccia samples with mass above 10 g in the LSLF vault.

A spinner magnetometer for large Apollo lunar samples

NASA Astrophysics Data System (ADS)

Uehara, M.; Gattacceca, J.; Quesnel, Y.; Lepaulard, C.; Lima, E. A.; Manfredi, M.; Rochette, P.

2017-10-01

We developed a spinner magnetometer to measure the natural remanent magnetization of large Apollo lunar rocks in the storage vault of the Lunar Sample Laboratory Facility (LSLF) of NASA. The magnetometer mainly consists of a commercially available three-axial fluxgate sensor and a hand-rotating sample table with an optical encoder recording the rotation angles. The distance between the sample and the sensor is adjustable according to the sample size and magnetization intensity. The sensor and the sample are placed in a two-layer mu-metal shield to measure the sample natural remanent magnetization. The magnetic signals are acquired together with the rotation angle to obtain stacking of the measured signals over multiple revolutions. The developed magnetometer has a sensitivity of 5 × 10-7 Am2 at the standard sensor-to-sample distance of 15 cm. This sensitivity is sufficient to measure the natural remanent magnetization of almost all the lunar basalt and breccia samples with mass above 10 g in the LSLF vault.

Estimating Attitude, Trajectory, and Gyro Biases in an Extended Kalman Filter using Earth Magnetic Field Data from the Rossi X-Ray Timing Explorer

NASA Technical Reports Server (NTRS)

Deutschmann, Julie; Bar-Itzhack, Itzhack

1997-01-01

Traditionally satellite attitude and trajectory have been estimated with completely separate systems, using different measurement data. The estimation of both trajectory and attitude for low earth orbit satellites has been successfully demonstrated in ground software using magnetometer and gyroscope data. Since the earth's magnetic field is a function of time and position, and since time is known quite precisely, the differences between the computed and measured magnetic field components, as measured by the magnetometers throughout the entire spacecraft orbit, are a function of both the spacecraft trajectory and attitude errors. Therefore, these errors can be used to estimate both trajectory and attitude. This work further tests the single augmented Extended Kalman Filter (EKF) which simultaneously and autonomously estimates spacecraft trajectory and attitude with data from the Rossi X-Ray Timing Explorer (RXTE) magnetometer and gyro-measured body rates. In addition, gyro biases are added to the state and the filter's ability to estimate them is presented.

EMIC wave events during the four QARBM challenge intervals

NASA Astrophysics Data System (ADS)

Engebretson, M. J.; Posch, J. L.; Braun, D.; Li, W.; Angelopoulos, V.; Kellerman, A. C.; Kletzing, C.; Lessard, M.; Mann, I. R.; Tero, R.; Shiokawa, K.; Wygant, J. R.

2017-12-01

We present observations of EMIC waves from multiple data sources during the four GEM challenge events in 2013 selected by the GEM focus group on Quantitative Assessment of Radiation Belt Modeling: March 17-18 (Stormtime Enhancement), May 31-June 2 (Stormtime Dropout), September 19-20 (Non-storm Enhancement), and September 23-25 (Non-storm Dropout). Observations include EMIC wave data from the Van Allen Probes and THEMIS spacecraft in the inner magnetosphere and from several arrays of ground-based search coil magnetometers worldwide, as well as localized ring current proton precipitation data from the low-altitude POES spacecraft. Each of these data sets provides only limited spatial coverage, but their combination reveals consistent occurrence patterns, which are then used to evaluate the effectiveness of EMIC waves in causing dropouts of radiation belt electrons during these GEM events.

A discussion of interplanetary post-shock flows with two examples. [with plasma and magnetometer observations

NASA Technical Reports Server (NTRS)

Ogilvie, K. W.; Burlaga, L. F.

1974-01-01

Plasma and magnetometer observations are described for two flare-associated shock flows and the comparison of them with models. One represents a class of flows where the shock is followed by a stream and separated from it by a region in which density temperature and speed decrease monotonically. The other is characterized by a complex region between the shock and the following stream, which has many discontinuities and fluctuations, but in which there is no increase in helium concentration. These two types of flow can be distinguished using ground magnetograms, since the former shows no sudden impulses following the shock, whereas the latter shows many.

Toward Quantum Non-demolition of nitrogen-vacancy centers in diamond

NASA Astrophysics Data System (ADS)

Hodges, Jonathan; Jiang, Liang; Maze, Jeronimo; Lukin, Mikhail

2009-05-01

The nitrogen-vacancy color center (NVC) in diamond, which possesses a long-lived electronic spin (S=1) ground state with optical addressability, is a promising platform for quantum networks, single-photon sources, and nanoscale magnetometers. Here, we make use of a nuclear spin based quantum memory to demonstrate quantum non-demolition measurement of a solid-state spin qubit. By entangling the electron spin with a polarized carbon-13 spin (I=1/2) in the lattice, we have repeated optical measurement of the electron spin for the polarization lifetime of the nuclear spin. We show relative improvements in signal-to-noise of greater than 300%. These techniques can be used to improve the sensitivity of NVC magnetometers.

Field-aligned currents associated with multiple arc systems

NASA Astrophysics Data System (ADS)

Wu, J.; Knudsen, D. J.; Gillies, D. M.; Donovan, E.; Burchill, J. K.

2016-12-01

It is often thought that auroral arcs are a direct consequence of upward field-aligned currents. In fact, the relation between currents and brightness is more complicated. Multiple auroral arc systems provide and opportunity to study this relation in detail; this information can be used as a test of models for quasi-static arc formation. In this study, we have identified two types of FAC configurations in multiple parallel arc systems using ground-based optical data from the THEMIS all-sky imagers (ASIs), magnetometers and electric field instruments onboard the Swarm satellites during the period from December 2013 to March 2015. In type 1 events, each arc is an intensification within a broad, unipolar current sheet and downward currents only exist outside the upward current sheet. In type 2 events, multiple arc systems represent a collection of multiple up/down current pairs. By collecting 12 events for type 1 and 17 events for type 2, we find that (1) Type 1 events are mainly located between 22-23MLT. Type 2 events are mainly located around midnight. (2) The typical size of upward and downward FAC in type 2 events are comparable, while upward FAC in type 1 events are larger than downward FAC. (3) Upward currents with more arcs embedded have larger intensities and widths. (4) There is no significant difference between the characteristic widths of multiple arcs and single arcs.

Pulsating midmorning auroral arcs, filamentation of a mixing region in a flank boundary layer, and ULF waves observed during a Polar-Svalbard conjunction

NASA Astrophysics Data System (ADS)

Farrugia, C. J.; Sandholt, P. E.; Maynard, N. C.; Burke, W. J.; Scudder, J. D.; Ober, D. M.; Moen, J.; Russell, C. T.

2000-12-01

Magnetically conjugate observations by the HYDRA and the Magnetic Field Experiment instruments on Polar, meridian-scanning photometers and all-sky imagers at Ny-Ålesund, and International Monitor for Auroral Geomagnetic Effects (IMAGE) magnetometers on November 30, 1997, illustrate aspects of magnetosphere-ionosphere coupling at 0900-1000 magnetic local times (MLT) and 70°-80° magnetic latitudes and their dependence on interplanetary parameters. Initially, Polar crossed a boundary layer on closed field lines where magnetospheric and magnetosheath plasmas are mixed. This region contains filaments where magnetospheric electron and ion fluxes are enhanced. These filaments are associated with field-aligned current structures embedded within the large-scale region 1 (R1) current. Ground auroral imagery document the presence at this time of discrete, east-west aligned arcs, which are in one-to-one correspondence with the filaments. Temporal variations present in these auroral arcs correlate with Pc 5 pulsations and are probably related to modulations in the interplanetary electric field. The auroral observations indicate that the filamented mixing region persisted for many tens of minutes, suggesting a spatial structuring. The data suggest further that the filamented, mixing region is an important source of the R1 current and the associated midmorning arcs. When the interplanetary magnetic field (IMF) turned strongly north, Polar had entered the dayside extension of the central plasma sheet/region 2 current system where it and the underlying ground magnetometers recorded a clear field line resonance of frequency ~2.4 mHz (Pc 5 range). The source of these oscillations is most likely the Kelvin-Helmholtz instability. Subsequent to the IMF northward turning, the multiple arcs were replaced by a single auroral form to the north of Ny-Ålesund (at 1000 MLT) in the vicinity of the westward edge of the cusp. ULF pulsation activity changed to the Pc 3-4 range in the regime of the pulsating diffuse aurora when the IMF went to an approximately Parker spiral orientation and the ground stations had rotated into the MLT sector of cusp emissions.

Development Of Eej Model Based On Dense Ground-based Magnetometer Array

NASA Astrophysics Data System (ADS)

Matsushita, H.; Yoshikawa, A.; Uozumi, T.; Fujimoto, A.; Abe, S.; Ishitsuka I, J. K.; Veliz, O.; Rosales, D.; Safor, E.; Beteta, V.

2016-12-01

Equatorial Electro-jet(here after called EEJ) is the electric current which flows very narrow region in ionosphere of the earth, which is between +- 3 degree from dip latitude. The EEJ was noticed as the significant enhancement of daily variation of magnetic field, and later Hirono, (1950) explained it by adapting Cowling effect to the ionosphere of the earth. The EE index, is one of ICSWSE space weather indices, was developed by Uozumi et al., (2008). Then, ICSWSE has continued to monitor the EEJ activity by using this EE index. Fujimoto et al., (2016) investigated the relationship between solar activity and long term variation of EEJ, and Hamid et al., (2015) investigated longitudinal dependency of EEJ, both of them were based on EE index. The EE index provides EDst value, which is correspond to magnetic field change at dip equator caused by magnetospheric current such as ring current, and EUEL value, which is correspond to the one caused by ionospheric current such as EEJ and Sq. However, actual EEJ is not magnetic field but the current, and it has not only current intensity but also the width. Some previous paper reported the EEJ structure such as current density or the width of EEJ using satellite data (e.g. Lühr et al., 2004; Jadhav et al., 2002), which is good when it checks the longitudinal dependency because it shifts longitude in a day. However, the ground-based magnetometer may be well useful to investigate the day-to-day variability of EEJ because it is fixed to same location. So, we developed a model of EEJ, which can estimate the EEJ current structure by ground magnetometer using dense magnetometer array near dip equator. In this study, the EEJ structures along 75W and 135E longitude are represented, and are compared each other. The result shows that large standard deviation of both current density and the half width are identified, while previous studies reported constant half width (e.g. Lühr et al., 2004). When our EEJ model is compared with CM4 model, which was developed by Sabaka et al., (2004), large discrepancy between them was identified, so it should be more discussed the reason to produce more accurate EEJ model.

155-mm M795 Aerofuze Test at the KOFA Range, Yuma Proving Ground, Arizona, 19 May 2015

DTIC Science & Technology

2017-09-01

public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions...including spin, pitch, yaw, and 3-axis acceleration in real time , data is relayed to a ground station using an integrated S-band transmitter. One unit...19.5 to 19.6 sec after time of fire 23 24 STFT spectrogram of magnetometer data during flight with peak frequency curve traced 24 25 Plots of battery

Through-barrier electromagnetic imaging with an atomic magnetometer.

PubMed

Deans, Cameron; Marmugi, Luca; Renzoni, Ferruccio

2017-07-24

We demonstrate the penetration of thick metallic and ferromagnetic barriers for imaging of conductive targets underneath. Our system is based on an 85 Rb radio-frequency atomic magnetometer operating in electromagnetic induction imaging modality in an unshielded environment. Detrimental effects, including unpredictable magnetic signatures from ferromagnetic screens and variations in the magnetic background, are automatically compensated by active compensation coils controlled by servo loops. We exploit the tunability and low-frequency sensitivity of the atomic magnetometer to directly image multiple conductive targets concealed by a 2.5 mm ferromagnetic steel shield and/or a 2.0 mm aluminium shield, in a single scan. The performance of the atomic magnetometer allows imaging without any prior knowledge of the barriers or the targets, and without the need of background subtraction. A dedicated edge detection algorithm allows automatic estimation of the targets' size within 3.3 mm and of their position within 2.4 mm. Our results prove the feasibility of a compact, sensitive and automated sensing platform for imaging of concealed objects in a range of applications, from security screening to search and rescue.

Magnetic observations at Geophysical Observatory Paratunka IKIR FEB RAS: tasks, possibilities and future prospects

NASA Astrophysics Data System (ADS)

Khomutov, Sergey Y.

2017-10-01

Continuous magnetic measurements at Geophysical Observatory "Paratunka" (PET) of IKIR FEB RAS are performed since 1967. In the new millennium analogue magnetometers were modernized to digital, the technologies of absolute observations were changed, the data processing was completely transferred to computers, and the status of INTERMAGNET observatory was obtained. Currently, the observatory uses the following magnetometers: (a) for absolute observations - DIflux LEMI-203 (theodolite 3T2KP) and Mag-01 (theodolite Wild-T1), Overhauser magnetometers POS-1 and GSM-19W; (b) for variation measurements - fluxgate magnetometers FGE-DTU, FRG-601 and MAGDAS (installed under international agreements of IKIR), vector magnetometers dIdD GSM-19FD and POS-4 with Overhauser sensors and coil systems, scalar magnetometer GSM-90 and induction magnetometer STELAB. During Spring-Autumn season dIdD also is installed at remote station "Karymshina" at distance of 15 km from Observatory. There is monitoring system for monitoring of conditions in which magnetic observations are performed, including the semi-professional weather stations Davis Vantage Pro2 and WS2000 and a network of digital temperature sensors DS19B20 located at various points in magnetic pavilions and outdoor. All measurements are synchronized with the UTC. The results of observations are collected by the IKIR data server from the recorders and loggers, including in real-time. Specialized software was developed (based on MATLAB and Octave packages), which allows automatic and semi-automatic processing of data, the comparison of the results from different magnetometers and presenting final data in formats, defined by international standards, including INTERMAGNET. Significant efforts of observatory staff are direct to archive (raw) magnetic data, a significant part of which has not been entirely processed, is not presented in international data centers and is still not available to the scientific community. Digital images of analog magnetograms have been obtained, the digitization of which allowed to fill the gaps in the hourly data available in the WDC for 1991, 1996-1997. The state of the set of the instruments and databases shows that the observatory "Paratunka" can solve most of the problems that arise in the geomagnetic field researches, including the provision of data for the development of regional and global field models, ground support of magnetometers located on satellites, support of the surface (sea) and aeromagnetic surveys and drilling, providing the data for researches of processes in the lithosphere, magnetosphere and ionosphere over a wide frequency range, and also for a number of applied problems. ARRAY(0x189e680)

Magnetic Field Observations at Purcell, Oklahoma Field Campaign Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chi, P. J.; Gibson, J. P.

The campaign “Magnetic Field Observations at Purcell, Oklahoma” installed a ground-based magnetometer at Purcell’s U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility boundary installation at the Kessler Atmospheric and Ecological Field Station, University of Oklahoma, to measure local magnetic field variations. It is a part of the nine stations of the Mid-continent MAgnetoseismic Chain (McMAC) placed as close to the 330° magnetic longitude as possible. This is the meridian in the world where land covers the greatest continuous range in magnetic latitude. Figure 1 shows the map of the magnetometer stations along the 330th magnetic meridian,more » including the Purcell (PCEL) station. The main scientific objective of the campaign is to detect the field line resonance (FLR) frequencies of the magnetic field line connected to the Purcell station. This magnetic field line extends from Purcell to the outer space at distances as far as 2 Earth radii (RE). To accurately identify FLR frequencies, however, simultaneous measurements at slightly different latitudes along the same meridian are necessary to allow the use of the cross-phase technique. This consideration explains the arrangement to operate magnetometers at the Americus (AMER) and Richardson (RICH) stations nearby. The measured resonant frequency can infer the plasma mass density along the field line through the method of normal-mode magnetoseismology. The magnetometer at the Purcell station can detect many other types of magnetic field fluctuations associated with the changes in the electric currents in the ionosphere and the magnetosphere, which by large are affected by the solar activity. In other words, the magnetic field data collected by this campaign are also useful for understanding space weather phenomena. The magnetometer was installed at Purcell’s ARM boundary facility in March 27, 2006. The construction of the triaxial fluxgate magnetometer used by the campaign, as well as the data processing and analysis, was sponsored by the National Science Foundation. Except during occasional downtimes, the magnetometer collected measurements from June 6, 2006 to July 26, 2016.« less

Magnetic measurements with fluxgate 3-components magnetometers in archaeology. Multi-sensor device and associated potential field operators for large scale to centimetre investigations on the 1st millennium BC site of Qasr ʿAllam in the western desert of

NASA Astrophysics Data System (ADS)

Gavazzi, Bruno; Alkhatib-Alkontar, Rozan; Munschy, Marc; Colin, Frédéric; Duvette, Catherine

2016-04-01

Fluxgate 3-components magnetometers allow vector measurements of the magnetic field. Moreover, they are the magnetometers measuring the intensity of the magnetic field with the lightest weight and the lowest power consumption. Vector measurements make them the only kind of magnetometer allowing compensation of magnetic perturbations due to the equipment carried with the magnetometer. Fluxgate 3-components magnetometers are common in space magnetometry and in aero-geophysics but are never used in archaeology due to the difficulty to calibrate them. This problem is overcome by the use of a simple calibration and compensation procedure on the field developed initially for space research (after calibration and compensation, rms noise is less than 1 nT). It is therefore possible to build a multi-sensor (up to 8) and georeferenced device for investigations at different scales down to the centimetre: because the locus of magnetic measurements is less than a cubic centimetre, magnetic profiling or mapping can be performed a few centimetres outside magnetized bodies. Such an equipment is used in a context of heavy sediment coverage and uneven topography on the 1st millennium BC site of Qasr ʿAllam in the western desert of Egypt. Magnetic measurements with a line spacing of 0.5 m allow to compute a magnetic grid. Interpretation using potential field operators such as double reduction to the pole and fractional vertical derivatives reveals a widespread irrigation system and a vast cultic facility. In some areas, magnetic profiling with a 0.1 m line spacing and at 0.1 m above the ground is performed. Results of interpretations give enough proof to the local authorities to enlarge the protection of the site against the threatening progression of agricultural fields.

Kilauea volcano, hawaii: a search for the volcanomagnetic effect.

PubMed

Davis, P M; Jackson, D B; Field, J; Stacey, F D

1973-04-06

Brief excursions of magnetic field differences between a base station and two satellite station magnetometers show only slight correlation with ground tilt at Kilauea Volcano. This result suggests that only transient, localized stresses occur during prolonged periods of deformation and that the volcano can support no large-scale pattern of shear stresses.

Geomagnetic Pulsations as Observed from Ground-Based Searchcoil Magnetometers (P52)

NASA Astrophysics Data System (ADS)

Sinha, A. K.; Pathan, B. M.; Vohat, P.

2006-11-01

ak50266@yahoo.com Magnetometer data from Searchcoil magnetometers in the Indian sectors have been analyzed to study geomagnetic pulsations in the low latitude region. On April 01 2005, we observe Pc 4 events at ~ 19 UT in the frequency range 10-15 mHz. The oscillations are seen in all the components (H, D, Z) indicating thereby that oscillations are compressional in nature. These pulsations are very much on the line of expectations at these latitudes. Apart from these normal pulsations, we observe the presence of pearl-type oscillations (~ 4 Hz) which is very unlikely at these latitude. These waves are common features of high latitude regions. The interesting aspect of these observed pearl-type features is that they follow a spike of broad-band source as revealed by the dynamic spectra. We are examining the role of thunderstorm lightening in generating these pearl-type pulses. Schumann resonances serve as indicators of lightning phenomena and we use their occurrences as parameter for lightening for correlating observed pulses to spiky broadband features preceding these pulses.

Energetics of the April 2000 magnetic superstorm observed by DMSP

NASA Astrophysics Data System (ADS)

Burke, William J.; Huang, Cheryl Y.; Rich, Frederick J.

2006-01-01

During the late main phase of the April 6, 2000 storm with Dst approaching -300 nT, four Defense Meteorological Satellite Program (DMSP) satellites encountered repeated episodes of intense field-aligned currents whose magnetic perturbations exceeded 1300 nT, corresponding to |J∥| > 1 A/m. They had relatively fast rise times (˜5 min) and lasted for ˜20 min. The large magnetic perturbations occurred within the expanded auroral oval at magnetic latitudes below 60°. From Poynting-flux calculations we estimate that during each event several hundred tera-Joules of energy that dissipates in the mid-latitude ionosphere and thermosphere. Ground magnetometers at auroral and middle latitudes detected weak fluctuations that were incommensurate with magnetic perturbations observations at DMSP altitudes. Observed discrepancies between ground and satellite magnetometer measurements suggest that under storm conditions operational models systematically underestimate the level of electromagnetic energy available to the ionosphere thermosphere. We demonstrate a transmission-line model for M-I coupling that allows calculations of this electromagnetic energy input with no a priori knowledge of ionospheric conductances.

Ground-based Instrumentations in Africa and its Scientific and Societal Benefits to the region

NASA Astrophysics Data System (ADS)

Yizengaw, Endawoke

2012-07-01

Much of what we know about equatorial physics is based on Jicamarca Incoherent Scattering Radar (ISR) observations. However, Jicamarca is in the American sector where the geomagnetic equator dips with a fairly large excursion between the geomagnetic and geodetic equator. On the other hand, in the African sector the geomagnetic equator is fairly well aligned with the geodetic equator. Satellites (e.g. ROCSAT, DMSP, C/NOFS) observations have also indicated that the equatorial ionosphere in the African sector responds differently than other sectors. However, these satellite observations have not been confirmed, validated or studied in detail by observations from the ground due to lack of suitable ground-based instrumentation in the region. Thus, the question of what causes or drives these unique density irregularities in the region is still not yet fully understood, leading the investigation of the physics behind each effect into speculative dead ends. During the past couple of years very few (compared to the land-mass that Africa covers) small instruments, like GPS receivers, magnetometers, VHF, and VLF have been either deployed in the region or in process. However, to understand the most dynamic region in terms of ionospheric irregularities, those few instruments are far from enough. Recently, significant progress has been emerging in securing more ground-based instrument into the region, and thus three ionosondes are either deployed or in process. In this paper, results from AMBER magnetometer network, ionosonde, and GPS receivers will be presented. By combining the multi instrument independent observations, this paper will show a cause and effect of space weather impact in the region for the first time. While the magnetometer network, such as those operated under the umbrella of AMBER project, estimates the fundamental electrodynamics that governs equatorial ionospheric motion, the GPS receivers will track the structure and dynamics of the ionosphere. In addition to the scientific importance, the ground-based instrumentations have also direct impact in advancing space science research by establishing and furthering sustainable research/training infrastructure within Africa so that more young scientists will be educated in their own country. The paper will present research results performed by graduate students who utilize data from the recently deployed instruments within the African universities.

Leveraging the Polar Cap: Ground-Based Measurements of the Solar Wind

NASA Astrophysics Data System (ADS)

Urban, K. D.; Gerrard, A. J.; Weatherwax, A. T.; Lanzerotti, L. J.; Patterson, J. D.

2016-12-01

In this study, we look at and identify relationships between solar wind quantities that have previously been shown to have direct access into the very high-latitude polar cap as measured by ground-based riometers and magnetometers in Antarctica: ultra-low frequency (ULF) power in the interplanetary magnetic field (IMF) Bz component and solar energetic proton (SEP) flux (Urban [2016] and Patterson et al. [2001], respectively). It is shown that such solar wind and ground-based observations can be used to infer the hydromagnetic structure and magnetospheric mapping of the polar cap region in a data-driven manner, and that high-latitude ground-based instrumentation can be used to infer concurrent various state parameters of the geospace environment.

Field Testing, Installation, and Calibration of a new Data Acquisition System for the USGS-Stanford-Berkley Ultra-Low Frequency Electromagnetic (ULFEM) Array

NASA Astrophysics Data System (ADS)

Creasy, N.; Gardner, J.; Spritzer, J. M.; Keneally, I.; Glen, J. M.; McPhee, D.; Klemperer, S. L.

2013-12-01

Since 2006, Stanford University, USGS, and UC Berkeley collaboratively maintain five permanent stations, to measure electric and magnetic data from 0.01 to 40Hz. Each station consists of three orthogonal coil magnetometers and two orthogonal 100m electrodes. The acquisition of ULFEM data helps study possible correlations between electromagnetic fields and seismic events related to the San Andreas Fault system. The current data acquisition system uses a Quanterra Q330 analog-to-digital converter. In 2010, we began development of a new 24-bit digitizing system known as the ULFEM 2010 digitizer in order to replace the Q330. The design of the new recorder was to be more economical and better tailored to the ULFEM network by providing power, calibration, and improved protection from lightning. However, the prototype had many problems, including a daily phase shift, amplifying error, and a time delay of 15 seconds (Bowden, et al., AGU, 2010). Currently, comparative testing of an improved prototype, ULFEM 2013, and the Q330 is taking place at the Jasper Ridge ULFEM station. The ULFEM 2013 contains eight channels that record input from three coil magnetometers, four electrodes, and temperature. Testing is ongoing and involves comparing the coil magnetometer and electrode signals processed by the Q330 and ULFEM 2013 digitizer. Data from the two systems will be compared in the time and frequency domains, and analyses will include calculating error and cross correlations. The ULFEM 2013 digitizer provides power to the magnetometer sensors as well as a calibration coil system (CCS). Every 24 hours, the CCS sends a calibration signal to calibration induction coils fitted to each of the three orthogonal magnetometers with the aim of testing the sensors' sensitivity and accuracy. The CCS produces a frequency sweep of 0.08, 0.51, 5, and 10Hz, creating a field nearly ten times greater than the Earth's field. The CCS consists of open source hardware and an amplifying frequency generator. Another ongoing effort to calibrate the ULFEM stations uses ground motion produced by distant earthquakes. Because of our stations' relatively close proximity (approximately 70km apart), teleseismic earthquakes at epicentral distances produce near-identical long-period seismic arrivals at each ULFEM station. The ground motion generated by the surface waves of distant earthquakes causes displacement of the induction coils, inducing magnetic anomalies in the recorded data. Because the ground motion has nearly the same characteristics at each station, the magnetic anomalies observed should have similar amplitudes regardless of the station (though modulated by the local conductivity structure at each site). To identify these coseismic signals, magnetic data were compared against seismic data from each station. Magnetic signals are clearly visible due to passage of Love and Rayleigh waves from teleseismic earthquakes of magnitude >7.4 and their relative amplitudes provide additional confirmation of the stability of our coils and recording system prior to the installation of the CCS.

The Study of the plasmaspheric refilling using the data from the ERG, the VAPs, the ground-based magnetometers and the IPE model

NASA Astrophysics Data System (ADS)

Obana, Y.; Maruyama, N.; Masahito, N.; Matsuoka, A.; Teramoto, M.; Nomura, R.; Fujimoto, A.; Tanaka, Y.; Shinohara, M.; Kasahara, Y.; Matsuda, S.; Kumamoto, A.; Tsuchiya, F.; Yoshizumi, M.; Shinohara, I.

2017-12-01

Earth's inner magnetosphere is a complex dynamical region of geo space comprising plasma populations with wide energy ranges, the plasmasphere, ring current, and radiation belts. They form a closely coupled system, thus, the plasmasphere is the lowest energy population in the inner magnetosphere, but the accurate prediction of the evolution of the plasmasphere is critical in understanding the dynamics of the inner magnetosphere, which include even the highest energy population, the radiation belts. In this study, we study plasmaspheric refilling following geomagnetic storms using data from ERG-MGF, ERG-PWE, RBSP-EMFISIS and Ground-based magneto­meters. DC magnetic field data measured by ERG-MGF, RBSP-EMFISIS and ground-based magnetometers provides the frequency of the toroidal mode field line resonances. From this information, the equatorial plasma mass density is estimated by solving the MHD wave equation for suitable models of the magnetic field and the field line density distribution. ERG-PWE and RBSP-EMFISIS provide measurements of wave electric and magnetic field, thus we can estimate the local electron density from the plasma wave spectrograms by identifying narrow-band emission at the upper-hybrid resonance frequency. Furthermore, using Ionosphere Plasmasphere Electrodynamics Model (IPE), we calculate the plasmaspheric refilling rates and evaluate the relative contribution of various mechanisms (heating, neutral particle density, composition and wings, etc.) to the refilling rate.

Continued Development of Meandering Winding Magnetometer (MWM (Register Trademark)) Eddy Current Sensors for the Health Monitoring, Modeling and Damage Detection of Composite Overwrapped Pressure Vessels

NASA Technical Reports Server (NTRS)

Russell, Richard; Wincheski, Russell; Jablonski, David; Washabaugh, Andy; Sheiretov, Yanko; Martin, Christopher; Goldfine, Neil

2011-01-01

Composite Overwrapped Pressure Vessels (COPVs) are used in essentially all NASA spacecraft, launch. vehicles and payloads to contain high-pressure fluids for propulsion, life support systems and science experiments. Failure of any COPV either in flight or during ground processing would result in catastrophic damage to the spacecraft or payload, and could lead to loss of life. Therefore, NASA continues to investigate new methods to non-destructively inspect (NDE) COPVs for structural anomalies and to provide a means for in-situ structural health monitoring (SHM) during operational service. Partnering with JENTEK Sensors, engineers at NASA, Kennedy Space Center have successfully conducted a proof-of-concept study to develop Meandering Winding Magnetometer (MWM) eddy current sensors designed to make direct measurements of the stresses of the internal layers of a carbon fiber composite wrapped COPV. During this study three different MWM sensors were tested at three orientations to demonstrate the ability of the technology to measure stresses at various fiber orientations and depths. These results showed good correlation with actual surface strain gage measurements. MWM-Array technology for scanning COPVs can reliably be used to image and detect mechanical damage. To validate this conclusion, several COPVs were scanned to obtain a baseline, and then each COPV was impacted at varying energy levels and then rescanned. The baseline subtracted images were used to demonstrate damage detection. These scans were performed with two different MWM-Arrays. with different geometries for near-surface and deeper penetration imaging at multiple frequencies and in multiple orientations of the linear MWM drive. This presentation will include a review of micromechanical models that relate measured sensor responses to composite material constituent properties, validated by the proof of concept study, as the basis for SHM and NDE data analysis as well as potential improvements including design changes to miniaturize and make the sensors durable in the vacuum of space

Swarm observation of field-aligned current and electric field in multiple arc systems

NASA Astrophysics Data System (ADS)

Wu, J.; Knudsen, D. J.; Gillies, M.; Donovan, E.; Burchill, J. K.

2017-12-01

It is often thought that auroral arcs are a direct consequence of upward field-aligned currents. In fact, the relation between currents and brightness is more complicated. Multiple auroral arc systems provide and opportunity to study this relation in detail. In this study, we have identified two types of FAC configurations in multiple parallel arc systems using ground-based optical data from the THEMIS all-sky imagers (ASIs), magnetometers and electric field instruments onboard the Swarm satellites during the period from December 2013 to March 2015. In type 1 events, each arc is an intensification within a broad, unipolar current sheet and downward currents only exist outside the upward current sheet. These types of events are termed "unipolar FAC" events. In type 2 events, multiple arc systems represent a collection of multiple up/down current pairs, which are termed as "multipolar FAC" events. Comparisons of these two types of FAC events are presented with 17 "unipolar FAC" events and 12 "multipolar FAC" events. The results show that "unipolar FAC" and "multipolar FAC" events have systematic differences in terms of MLT, arc width and separation, and dependence on substorm onset time. For "unipolar FAC" events, significant electric field enhancements are shown on the edges of the broad upward current sheet. Electric field fluctuations inside the multiple arc system can be large or small. For "multipolar FAC" events, a strong correlation between magnetic and electric field indicate uniform conductance within each upward current sheet. The electrodynamical structures of multiple arc systems presented in this paper represents a step toward understanding arc generation.

The Mesospheric Sodium Layer as a Remotely, Optically Pumped Magnetometer for Investigation of Birkeland Currents

NASA Astrophysics Data System (ADS)

Matzka, J.; Johnsen, M. G.; Hoppe, U. P.; Serrano, A.

2016-12-01

By means of optical pumping, it is possible to use the naturally occurring sodium layer in the mesosphere to measure Earth's scalar magnetic field at 90 km above ground. This is an altitude not accessible by other means than rockets, which only will provide point measurements of very short time scales. We are planning to modify the sodium lidar at ALOMAR in Northern Norway to be able, for the first time, to measure and monitor the magnetic field in situ in the high latitude mesosphere over longer time scales. The planned modifications to the lidar instrument will allow alternating between the new magnetometer mode and its present mode for atmospheric temperatures and winds. The technique, which has been proposed earlier for measurements at low or mid-latitudes for studies of Earth's internal magnetic field, will in our project be applied to high latitudes in the auroral zone. This opens for a completely new domain of measurements of externally generated geomagnetic variations related to currents in the magnetosphere-ionosphere system. In particular, we aim to measure the magnetic field variations in close vicinity to Birkeland currents associated with particle precipitation events penetrating to altitudes below 90 km and small-scale, discrete auroral arcs. It is, furthermore, anticipated that it will be possible to detect horizontal current structures in the E-layer on much smaller length scales than it is presently possible from ground observations alone. During the project we plan take advantage of the rich space science infrastructure located in northern Norway, including ALOMAR, EISCAT and the Tromsø Geophysical Observatory magnetometer network. If possible, we also aim to make measurements in conjunction with overpasses of the SWARM satellites.

POLAR-UVI and other Coordinated Observations of a Traveling Convection Vortex Event Observed on 24 July 1996

NASA Technical Reports Server (NTRS)

Clauer, C. R.; Baker, J. B.; Ridley, A. J.; Sitar, R. J.; Papitashvili, V. O.; Cumnock, J.; Spann, J. F., Jr.; Brittnacher, M. J.; Parks, G. K.

1997-01-01

Coordinated analysis of data from the POLAR UVI instrument, ground magnetometers, incoherent scatter radar, solar wind monitors IMP-8 and WIND, and DMSP satellite is focused on a traveling convection vortex (TCV) event on 24 July 1966. Starting at 10:48 UT, ground magnetometers in Greenland and eastern Canada measure pulsations consistent with the passing overhead of a series of alternating TCV field-aligned current pairs. Sondrestrom incoherent scatter radar measures strong modulation of the strength and direction of ionospheric plasma flow, The magnetometer pulsations grow in magnitude over the next hour, peaking in intensity at 11:39 UT, at which time the UVI instrument measures a localized intensification of auroral emissions over central and western Greenland. Subsequent images show the intensification grow in strength and propagate westward (tailward) until approximately 11:58 UT at which time the emissions fade. These observations are consistent with the westward passage of two pairs of moderately intense TCVs over central Greenland followed by a third very intense TCV pair. The intensification of auroral emissions at 11:39 UT is associated with the trailing vortex of the third TCV pair, thought to be the result of an upward field-aligned current. Measurements of the solar wind suggest that a pressure change may be responsible for triggering the first two pairs of TCVS, and that a subsequent sudden change in orientation of the IMF may have produced the intensification of the third TCV pair and the associated aurora] brightening. DMSP particle data indicate that the TCVs occur on field lines which map to the boundary plasma sheet or outer edge of the low latitude boundary layer.

A Collaborative Approach for Providing Low-Cost ELF Monitoring from Ground and Space

NASA Astrophysics Data System (ADS)

Bleier, T. E.; Franklin, L.

2003-12-01

This paper describes a collaborative effort among several groups, including a small business (QuakeFinder,LLC), dozens of high schools in northern California, several universities (Stanford and Cal Poly SLO), and Lockheed Martin in Sunnyvale to build a combined ground-based and space-based ELF monitoring system. The goal is to monitor and characterize the raw RF spectrum in the ELF band, and to look for pre- and post-earthquake signatures. Previous attempts at monitoring ELF signals associated with earthquakes have always been summarized with the statement, more data is needed. QuakeFinder is a small business that approached the problem with a different strategy. Rather than deploy a few, expensive, commercial high sensitivity, AC magnetometers on the ground, a collaboration was formed with high school physics classes to build a large number of medium sensitivity magnetometers from partially-assembled kits, and to deploy these sensors in a close spacing along the major California earthquake faults. The strategy was to have a 3-axis ELF ground monitor within 15 km of any large (>M5) quake-- before, during, and after the event. To date, 34 sites have been deployed (out of 50 planned), and they now collect and display daily averages from these 3-axis monitors on a web site (www.earthquaketracker.com). Likewise, satellite-based monitoring is severely restricted by the high cost of building and flying space-based ELF monitors. QuakeFinder formed a collaboration between Stanford Space System Development Laboratory and Lockheed Martin to design and build a nano-satellite (4.5 kg) whose mission was to collect ELF background signatures. QuakeFinder built and donated a single axis ELF (1-1000Hz) magnetometer payload and provided integration and a launch opportunity for "QuakeSat I". The satellite was launched on June 30, 2003 into a 820 km circular polar orbit, and has recorded natural signals (lightning, whistlers, auroral noise, and several unidentified signatures) as well as man-made (radar) signals. At this writing, it is early in the project, and more signal analysis and statistics are needed to determine if earthquake-related signals are present. The paper will report on the result of QuakeSat tasking over epicenters of >M6 earthquakes for post seismic correlations, and over seismically active areas worldwide for pre-seismic correlations of increasing ELF signals.

TrackPlot Enhancements: Support for Multiple Animal Tracks and Gyros

DTIC Science & Technology

2015-09-30

visualization and kinematic analysis of marine animal movements derived from archival tag data. Tags are supported that have sensors for pressure, acceleration...1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. TrackPlot Enhancements: Support for Multiple Animal ...in combination with accelerometer and magnetometer data. 2) the extraction and frequency analysis of accelerations and rotation in animal

Fusion of magnetometer and gradiometer sensors of MEG in the presence of multiplicative error.

PubMed

Mohseni, Hamid R; Woolrich, Mark W; Kringelbach, Morten L; Luckhoo, Henry; Smith, Penny Probert; Aziz, Tipu Z

2012-07-01

Novel neuroimaging techniques have provided unprecedented information on the structure and function of the living human brain. Multimodal fusion of data from different sensors promises to radically improve this understanding, yet optimal methods have not been developed. Here, we demonstrate a novel method for combining multichannel signals. We show how this method can be used to fuse signals from the magnetometer and gradiometer sensors used in magnetoencephalography (MEG), and through extensive experiments using simulation, head phantom and real MEG data, show that it is both robust and accurate. This new approach works by assuming that the lead fields have multiplicative error. The criterion to estimate the error is given within a spatial filter framework such that the estimated power is minimized in the worst case scenario. The method is compared to, and found better than, existing approaches. The closed-form solution and the conditions under which the multiplicative error can be optimally estimated are provided. This novel approach can also be employed for multimodal fusion of other multichannel signals such as MEG and EEG. Although the multiplicative error is estimated based on beamforming, other methods for source analysis can equally be used after the lead-field modification.

Miniature atomic scalar magnetometer for space based on the rubidium isotope 87Rb.

PubMed

Korth, Haje; Strohbehn, Kim; Tejada, Francisco; Andreou, Andreas G; Kitching, John; Knappe, Svenja; Lehtonen, S John; London, Shaughn M; Kafel, Matiwos

2016-08-01

A miniature atomic scalar magnetometer based on the rubidium isotope 87 Rb was developed for operation in space. The instrument design implements both M x and M z mode operation and leverages a novel microelectromechanical system (MEMS) fabricated vapor cell and a custom silicon-on-sapphire (SOS) complementary metal-oxide-semiconductor (CMOS) integrated circuit. The vapor cell has a volume of only 1 mm 3 so that it can be efficiently heated to its operating temperature by a specially designed, low-magnetic-field-generating resistive heater implemented in multiple metal layers of the transparent sapphire substrate of the SOS-CMOS chips. The SOS-CMOS chip also hosts the Helmholtz coil and associated circuitry to stimulate the magnetically sensitive atomic resonance and temperature sensors. The prototype instrument has a total mass of fewer than 500 g and uses less than 1 W of power, while maintaining a sensitivity of 15 pT/√Hz at 1 Hz, comparable to present state-of-the-art absolute magnetometers.

Agreements between ground-based and satellite-based observations. [of earth magnetospheric currents

NASA Technical Reports Server (NTRS)

Akasofu, S.-I.; Weimer, D.; Iijima, T.; Ahn, B.-H.; Kamide, Y.

1990-01-01

The polar ionospheric parameters obtained by the meridian chain of magnetometers are compared with those obtained by satellites, and a number of ionospheric quantities including the distribution of the electric potential, field-aligned currents, ionospheric currents and their equatorial counterparts, and the relationship between the AE index and the cross-polar cap potential is determined. It is noted that the agreement observed between the ground-based and satellite-based results allows to reduce the search for the driving mechanism of the ionospheric Pedersen current to identifying the driving mechanism of the Pedersen counterpart current in the equatorial plane.

Ground Vehicle Navigation Using Magnetic Field Variation

DTIC Science & Technology

2012-09-13

points on the sphere to resolve the calibration parameters. This approach is nearly identical to 5 Vasconcelos [44]. Additionally, the composition of...possible. 1.1.5 Three-axis Magnetometer Calibration. Vasconcelos et al., addressed three-dimensional ellipsoid calibration techniques for...Strangway, David W. History of the Earth’s Magnetic Field. McGraw-Hill, Inc., New York, NY, 1970. 44. Vasconcelos , J.F., G. Elkaim, C. Silvestre, P

Methods for Finding Legacy Wells in Large Areas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hammack, Richard W.; Veloski, Garret A.; Hodges, D. Greg

United States. When abandoned, many wells were not adequately sealed and now provide a potential conduit for the vertical movement of liquids and gases. Today, groundwater aquifers can be contaminated by surface pollutants flowing down wells or by deep, saline water diffusing upwards. Likewise, natural gas, carbon dioxide (CO2), or radon can travel upwards via these wells to endanger structures or human health on the surface. Recently, the need to find and plug wells has become critical with the advent of carbon dioxide injection into geologic formations for enhanced oil recovery (EOR) or carbon storage. The potential for natural gasmore » or brine leakage through existing wells has also been raised as a concern in regions where shale resources are hydraulically fractured for hydrocarbon recovery. In this study, the National Energy Technology Laboratory (NETL) updated existing, effective well finding techniques to be able to survey large areas quickly using helicopter or ground-vehicle-mounted magnetometers, combined with mobile methane detection. For this study, magnetic data were collected using airborne and ground vehicles equipped with two boom-mounted magnetometers, or on foot using a hand-held magnetometer with a single sensor. Data processing techniques were employed to accentuate well-casing-type magnetic signatures. To locate wells with no magnetic signature (wells where the steel well casing had been removed), the team monitored for anomalous concentrations of methane, which could indicate migration of volatile compounds from deeper sedimentary strata along a well or fracture pathway. Methane measurements were obtained using the ALPIS DIfferential Absorption Lidar (DIAL) sensor for helicopter surveys and the Apogee leak detection system (LDS) for ground surveys. These methods were evaluated at a 100-year-old oilfield in Wyoming, where a helicopter magnetic survey accurately located 93% of visible wells. In addition, 20% of the wells found by the survey were previously unknown or inaccurately located. This study found helicopter magnetic surveys to be an accurate, cost- and time-effective means to locate steel-cased wells in large areas, and is a first step in evaluating whether well detection techniques can be applied effectively for well location screening across broad geographic areas.« less

Magnetometer Data in the Classroom as a part of the NASA THEMIS Satellite Mission

NASA Astrophysics Data System (ADS)

Peticolas, L. M.; Bean, J.; Walker, A.

2011-12-01

The NASA-funded THEMIS mission was designed to determine the onset time and location of magnetic substorms of Earth's space environment, a prerequisite to understanding space weather. THEMIS is an acronym for Time History of Events and Macroscale Interactions during Substorms. he Geomagnetic Event Observation Network by Students (GEONS) project was the flagship, formal education component of the E/PO program. With the placement of magnetometers in the proximity of rural schools throughout the country, middle and high school teachers along with their students benefited from the opportunity to work with 'real-time' data and participated in hands-on space science activities. Particular attention was paid to placing the magnetometer stations at schools in rural communities whose students were traditionally underserved and underrepresented in the sciences. The project offered to the teachers of these students long-term professional development opportunities that centered around THEMIS-related space science and the magnetometer data. The THEMIS E/PO final evaluation report for the main phase of the THEMIS mission covered the period from 2003-2009, describing the impact of this program such as this program placed magnetometers sites at 13 rural, underserved schools/communities, two-fifths of which are on tribal lands; and provided intensive professional development for 20 teachers from 2004 through 2009. A core group of eight teachers estimated reaching more than 2,720 students with THEMIS-related materials/ideas. 75% of these students are minorities in science. Core teachers provided evidence of the project's positive impact on students' attitudes toward science and their choices for courses that position them for STEM-related careers. Core teachers reported sharing THEMIS-related materials/ideas with 275 colleagues. The NewsHour with Jim Lehrer featured the Petersburg, Alaska site potentially reaching more than 5 million viewers in two airings, according to Nielsen ratings. The PBS NewsHour piece was picked up by National Public Radio and made available on the Online NewsHour Web site where it was linked to NOVA Science NOW's Web site. Nearly all core teachers have become involved in other NASA-related programs-Heliophysics Educator Ambassadors, GSFC's Cosmic Times, SOPHIA, RBSE, etc. Jim Bean, one of the teachers in the program, highlights the benefits of this program in the classroom as: 1) inquiry/application based learning at an advanced high school level (physics; magnetism-B-field, electromagnetic radiation), 2) real-time data collection from multiple sources, i.e. Magnetometers, SOHO, iPhone and other phone Applications, etc., 3) data analysis, vector analysis, graphical representations, and 4) multiple subject integration; physics, math, geology, and astronomy.

ULTIMA: Array of ground-based magnetometer arrays for monitoring magnetospheric and ionospheric perturbations on a global scale

NASA Astrophysics Data System (ADS)

Yumoto, K.; Chi, P. J.; Angelopoulos, V.; Connors, M. G.; Engebretson, M. J.; Fraser, B. J.; Mann, I. R.; Milling, D. K.; Moldwin, M. B.; Russell, C. T.; Stolle, C.; Tanskanen, E.; Vallante, M.; Yizengaw, E.; Zesta, E.

2012-12-01

ULTIMA (Ultra Large Terrestrial International Magnetic Array) is an international consortium that aims at promoting collaborative research on the magnetosphere, ionosphere, and upper atmosphere through the use of ground-based magnetic field observatories. ULTIMA is joined by individual magnetometer arrays in different countries/regions, and the current regular-member arrays are Australian, AUTUMN, CARISMA, DTU Space, Falcon, IGPP-LANL, IMAGE, MACCS, MAGDAS, McMAC, MEASURE, THEMIS, and SAMBA. The Chair of ULTIMA has been K. Yumoto (MAGDAS), and its Secretary has been P. Chi (McMAC, Falcon). In this paper we perform case studies in which we estimate the global patterns of (1) near-Earth currents and (2) magnetic pulsations; these phenomena are observed over wide areas on the ground, thus suitable for the aims of ULTIMA. We analyze these two phenomena during (a) quiet period and (b) magnetic storm period. We compare the differences between these two periods by drawing the global maps of the ionospheric equivalent currents (which include the effects of all the near-Earth currents) and pulsation amplitudes. For ionospheric Sq currents at low latitudes during quiet periods, MAGDAS data covering an entire solar cycle has yielded a detailed statistical model, and we can use it as a reference for the aforementioned comparison. We also estimate the azimuthal wave numbers of pulsations and compare the amplitude distribution of pulsations with the distribution of highly energetic (in MeV range) particles simultaneously observed at geosynchronous satellites.

Long-term biases in geomagnetic K and aa indices

USGS Publications Warehouse

Love, J.J.

2011-01-01

Analysis is made of the geomagnetic-activity aa index and its source K-index data from groups of ground-based observatories in Britain, and Australia, 1868.0-2009.0, solar cycles 11-23. The K data show persistent biases, especially for high (low) K-activity levels at British (Australian) observatories. From examination of multiple subsets of the K data we infer that the biases are not predominantly the result of changes in observatory location, localized induced magnetotelluric currents, changes in magnetometer technology, or the modernization of K-value estimation methods. Instead, the biases appear to be artifacts of the latitude-dependent scaling used to assign K values to particular local levels of geomagnetic activity. The biases are not effectively removed by weighting factors used to estimate aa. We show that long-term averages of the aa index, such as annual averages, are dominated by medium-level geomagnetic activity levels having K values of 3 and 4. ?? 2011 Author(s).

Multiple ground-based and satellite observations of global Pi 2 magnetic pulsations

NASA Technical Reports Server (NTRS)

Yumoto, K.; Takahashi, K.; Sakurai, T.; Sutcliffe, P. R.; Kokubun, S.

1990-01-01

Four Pi 2 events are examined using data obtained concurrently at the Syowa-Iceland conjugate stations, the EISCAT-Magnetometer Cross, low-latitude stations HER on the nightside and KAK on the dayside, and at AMPTE/CCE in the outer magnetosphere during the period from 2300 UT on May 22 to 0300 UT on May 23, 1985. Several characteristics of Pi 2 are established on the basis of high time resolution magnetic field data. First of all, horizontal components, H and D, of the Pi 2 oscillate nearly antiphase and in-phase, respectively, between the high- and low-altitude stations in the midnight southern hemisphere. Both H and D components of the Pi 2 have nearly in-phase relationships between the nightside and the dayside stations at low altitude. The Pi 2 amplitude is larger at the high-latitude station and decreases toward low latitudes. The dominant periods of the Pi 2 are nearly identical at all stations.

Auroral Substorms during Prolonged Northward IMF

NASA Astrophysics Data System (ADS)

Du, Aimin

Multiple observations by satellites and ground-based magnetometers identify the occurrence of substorm events during prolonged northward interplanetary magnetic field (IMF). The func-tion, as an expression of the solar wind energy flow, and the energy dissipation in the ionosphere (UI) are calculated during substorm periods. The delay time of the UI to the function and UI for seven substorm events with AL values of -231 -1500 nT under northward IMF condition are 45 95 min with a mean value of 70.86 min. For comparison, 23 substorm events with the AL index of -316 -1685 nT under southward IMF condition are detected to have the delay time of 21 66 min with a mean value of 42.04 min. The longer delay time for substorms during northward IMF can be presumably attributed to the contribution of IMF By component to merging between IMF and the Earth's magnetic field. A tendency of the decrease of the delay time with increasing absolute values of IMF By is noted. Acknowledgement: This work is supported by NSFC(40774086).

Space Technology 5 Post-Launch Ground Attitude Estimation Experience

NASA Technical Reports Server (NTRS)

Harman, Richard R.

2007-01-01

The Space Technology (ST)-5 satellites were launched March 22, 2006 on a Pegasus XL launch vehicle into a Sun-synchronous orbit. The three micro-satellites which constituted the ST-5 mission were kept in a formation which allowed three successive measurements taken of the Earth s magnetic field in order to study short term fluctuations of the field. The attitude of each satellite was computed on the ground using data from the science grade magnetometer as well as the miniature spinning Sun sensor (MSSS) which was the primary attitude sensor. Attitude and orbit maneuvers were performed using a single axial cold gas thruster. This paper describes the ground attitude estimation process and performance as well as anomaly resolutions.

Investigation of a low-cost magneto-inductive magnetometer for space science applications

NASA Astrophysics Data System (ADS)

Regoli, Leonardo H.; Moldwin, Mark B.; Pellioni, Matthew; Bronner, Bret; Hite, Kelsey; Sheinker, Arie; Ponder, Brandon M.

2018-03-01

A new sensor for measuring low-amplitude magnetic fields that is ideal for small spacecraft is presented. The novel measurement principle enables the fabrication of a low-cost sensor with low power consumption and with measuring capabilities that are comparable to recent developments for CubeSat applications. The current magnetometer, a software-modified version of a commercial sensor, is capable of detecting fields with amplitudes as low as 8.7 nT at 40 Hz and 2.7 nT at 1 Hz, with a noise floor of 4 pT/Hz at 1 Hz. The sensor has a linear response to less than 3 % over a range of ±100 000 nT. All of these features make the magneto-inductive principle a promising technology for the development of magnetic sensors for both space-borne and ground-based applications to study geomagnetic activity.

Towards a Radiation Hardened Fluxgate Magnetometer for Space Physics Applications

NASA Astrophysics Data System (ADS)

Miles, David M.

Space-based measurements of the Earth's magnetic field are required to understand the plasma processes of the solar-terrestrial connection which energize the Van Allen radiation belts and cause space weather. This thesis describes a fluxgate magnetometer payload developed for the proposed Canadian Space Agencys Outer Radiation Belt Injection, Transport, Acceleration and Loss Satellite (ORBITALS) mission. The instrument can resolve 8 pT on a 65,000 nT field at 900 samples per second with a magnetic noise of less than 10 pT per square-root Hertz at 1 Hertz. The design can be manufactured from radiation tolerant (100 krad) space grade parts. A novel combination of analog temperature compensation and digital feedback simplifies and miniaturises the instrument while improving the measurement bandwidth and resolution. The prototype instrument was successfully validated at the Natural Resources Canada Geomagnetics Laboratory, and is being considered for future ground, satellite and sounding rocket applications.

Magnetic and GPR surveys of a former munitions foundry site at the Denver Federal Center

USGS Publications Warehouse

Campbell, David L.; Beanland, Shay; Lucius, Jeffrey E.; Powers, Michael H.

2000-01-01

We made magnetometer and ground penetrating radar (GPR) surveys over part of the foundation of a World War II-era foundry located on the Denver Federal Center. The site contains a number of highly magnetic source bodies, concrete foundation walls, and underground openings, buried under a clay cap. The cap is several feet thick and has a conductivity of about 35 mS/m, making the features underneath it a poor target for conventional GPR. Indeed, the raw data look unlike typical GPR data, but rather show reverberation (?) bands under sidewalks and other shallow buried sources. Using a newly-written computer package, we made plan maps of the GPR response at different time slices. The sliced GPR data did not outline buried foundry foundations, as we had hoped it might. The resulting plan maps of the sliced data show sidewalks and other blobby features, some of which correspond to magnetometer highs.

Swarm Observation of Field-Aligned Currents Associated With Multiple Auroral Arc Systems

NASA Astrophysics Data System (ADS)

Wu, J.; Knudsen, D. J.; Gillies, D. M.; Donovan, E. F.; Burchill, J. K.

2017-10-01

Auroral arcs occur in regions of upward field-aligned currents (FACs); however, the relation is not one to one, since kinetic energy of the current-carrying electrons is also important in the production of auroral luminosity. Multiple auroral arc systems provide an opportunity to study the relation between FACs and auroral brightness in detail. In this study, we have identified two types of FAC configurations in multiple parallel arc systems using ground-based optical data from the Time History of Events and Macroscale Interactions during Substorms all-sky imagers, magnetometers and electric field instruments on board the Swarm satellites. In "unipolar FAC" events, each arc is an intensification within a broad, unipolar current sheet and downward return currents occur outside of this broad sheet. In "multipolar FAC" events, multiple arc systems represent a collection of multiple up/down current pairs. By collecting 17 events with unipolar FAC and 12 events with multipolar FACs, we find that (1) unipolar FAC events occur most frequently between 20 and 21 magnetic local time and multipolar FAC events tend to occur around local midnight and within 1 h after substorm onset. (2) Arcs in unipolar FAC systems have a typical width of 10-20 km and a spacing of 25-50 km. Arcs in multipolar FAC systems are wider and more separated. (3) Upward currents with more arcs embedded have larger intensities and widths. (4) Electric fields are strong and highly structured on the edges of multiple arc system with unipolar FAC. The fact that arcs with unipolar FAC are much more highly structured than the associated currents suggests that arc multiplicity is indicative not of a structured generator deep in the magnetosphere, but rather of the magnetosphere-ionosphere coupling process.

Standardized UXO Technology Demonstration Site Blind Grid Scoring Record Number 891

DTIC Science & Technology

2008-08-01

magnetometers (Foerster CON650 gradiometers) and RTK-DGPS georeferencing will be used. The spacing between the individual fluxgate sensors will be 25 cm...used for data acquisition usually ranges from 8 to 32. b. For the demonstration at Aberdeen Proving Ground, a system with eight fluxgate ...up to 32 fluxgate gradiometers (for the APG demonstration: eight fluxgate gradiometers), a robust, all-terrain trailer, the MonMX data acquisition

Conjugate observations of electromagnetic ion cyclotron waves associated with traveling convection vortex events

NASA Astrophysics Data System (ADS)

Kim, Hyomin; Clauer, C. Robert; Gerrard, Andrew J.; Engebretson, Mark J.; Hartinger, Michael D.; Lessard, Marc R.; Matzka, Jürgen; Sibeck, David G.; Singer, Howard J.; Stolle, Claudia; Weimer, Daniel R.; Xu, Zhonghua

2017-07-01

We report on simultaneous observations of electromagnetic ion cyclotron (EMIC) waves associated with traveling convection vortex (TCV) events caused by transient solar wind dynamic pressure (Pd) impulse events. The Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft located near the magnetopause observed radial fluctuations of the magnetopause, and the GOES spacecraft measured sudden compressions of the magnetosphere in response to sudden increases in Pd. During the transient events, EMIC waves were observed by interhemispheric conjugate ground-based magnetometer arrays as well as the GOES spacecraft. The spectral structures of the waves appear to be well correlated with the fluctuating motion of the magnetopause, showing compression-associated wave generation. In addition, the wave features are remarkably similar in conjugate hemispheres in terms of bandwidth, quasiperiodic wave power modulation, and polarization. Proton precipitation was also observed by the DMSP spacecraft during the wave events, from which the wave source region is estimated to be 72°-74° in magnetic latitude, consistent with the TCV center. The confluence of space-borne and ground instruments including the interhemispheric, high-latitude, fluxgate/induction coil magnetometer array allows us to constrain the EMIC source region while also confirming the relationship between EMIC waves and the TCV current system.

A Research and Development Strategy for Unexploded Ordnance Sensing

DTIC Science & Technology

1996-04-01

Each lane was carefully traversed with the MK-26 Ordnance Detector (dual fluxgate magnetometer hand-held unit) and the operator hand-excavated any...proton-precessing magnetometers , optically pumped magnetometers , fluxgates magnetometers , and magnetometers based on superconducting quantum...sensitivity better than 0.05 nT, and the optically-pumped magnetometers have sensitivity better than 0.005 nT. Fluxgate magnetometers are based on solid

Investigation of GICs Associated with Large dB/dt Variations in Space

NASA Astrophysics Data System (ADS)

Dimitrakoudis, S.; Mann, I. R.; Murphy, K. R.; Rae, J.; Denton, M.; Milling, D. K.

2016-12-01

Geomagnetically induced currents (GICs) can be driven in terrestrial electrical power grids as a result of the induced electric fields arising from magnetic field changes driven in the coupled magnetosphere-ionosphere-ground system. Substorms are often hypothesised to be associated with the largest GIC effects on the ground, especially at higher latitudes. However, recent studies have suggested that other dayside phenomena such as sudden impulses and even ULF wave trains might also drive significant GICs. Using data from the CARISMA ground-based magnetometer network we examine the GIC response driven from a variety of magnetospheric processes. In particular we focus on events where large dB/dt is observed in-situ on GOES East and West satellites. Auroras, resulting from magnetospheric substorms, give us a dynamical view of sudden destabilizations in the nightside magnetosphere, of large spatial and temporal extent, that can drive large and potentially damaging geomagnetically induced currents (GICs) in terrestrial power grids. Since ground dB/dt can be used as a GIC proxy, we have surveyed GOES data since 2011 for the largest dB/dT events, and found some to be of the order of hundreds of nT in the span of a few seconds. These are observed in both the nightside and dayside, and, as such, we seek to establish connections to drivers affecting both sides of the terminator; tail activations and substorms on the nightside, large amplitude ULF waves, solar wind sudden impulses, and rapid changes in MIC current systems on the dayside. The short duration of these events, coupled with the use of conjugate satellite measurements and ground magnetometer arrays when possible, allows us to investigate their localization and the latitudinal extent of their effects and to further examine the potential role of non-substorm phenomena in generating GICs which may have adverse impacts in electrical power grids.

Using Redundancy To Reduce Errors in Magnetometer Readings

NASA Technical Reports Server (NTRS)

Kulikov, Igor; Zak, Michail

2004-01-01

A method of reducing errors in noisy magnetic-field measurements involves exploitation of redundancy in the readings of multiple magnetometers in a cluster. By "redundancy"is meant that the readings are not entirely independent of each other because the relationships among the magnetic-field components that one seeks to measure are governed by the fundamental laws of electromagnetism as expressed by Maxwell's equations. Assuming that the magnetometers are located outside a magnetic material, that the magnetic field is steady or quasi-steady, and that there are no electric currents flowing in or near the magnetometers, the applicable Maxwell 's equations are delta x B = 0 and delta(raised dot) B = 0, where B is the magnetic-flux-density vector. By suitable algebraic manipulation, these equations can be shown to impose three independent constraints on the values of the components of B at the various magnetometer positions. In general, the problem of reducing the errors in noisy measurements is one of finding a set of corrected values that minimize an error function. In the present method, the error function is formulated as (1) the sum of squares of the differences between the corrected and noisy measurement values plus (2) a sum of three terms, each comprising the product of a Lagrange multiplier and one of the three constraints. The partial derivatives of the error function with respect to the corrected magnetic-field component values and the Lagrange multipliers are set equal to zero, leading to a set of equations that can be put into matrix.vector form. The matrix can be inverted to solve for a vector that comprises the corrected magnetic-field component values and the Lagrange multipliers.

Quantifying Hemispheric Asymmetry of Auroral Currents by Polar Region Interhemispheric Magnetic Observatories (PRIMO)

NASA Astrophysics Data System (ADS)

Chi, P. J.; Russell, C. T.; Strangeway, R. J.; Connors, M. G.; Wilson, T. J.; Angelopoulos, V.; Anderson, B. J.; Kadokura, A.

2016-12-01

Previous observations have demonstrated that substorm auroras and the associated electric currents can exhibit substantial north-south asymmetry. Possible mechanisms that cause this asymmetry include the penetration of IMF By into the magnetotail, the difference in ionospheric conductivity due to the dipole tilt angle, and the difference in solar wind dynamo efficiency due to IMF Bx combined with the tilt angle. The relative importance of these factors, however, has not been determined, due to paucity of observations in the southern hemisphere. To resolve this difficulty, we propose to establish three new stations in West Antarctica for measuring geomagnetic perturbations. The three magnetometer stations are located at Lepley Lunatak, Union Glacier, and Whitmore Mountains, between -2° W and 7° W magnetic longitude at L-values 4, 6, and 8. These locations are magnetically conjugate to the recently established AUTUMNX magnetometers along the eastern shore of the Hudson Bay, enabling unique conjugate observations by two magnetometer chains at auroral latitudes and subauroral latitudes when close to midnight. These conjugate magnetic field observations, with concurrent satellite measurements by the AMPERE constellation and the Heliophysics System Observatory, can differentiate between magnetospheric and ionospheric contributions in the hemispheric asymmetry. The comparison with the conjugate observations at the Syowa and Iceland stations can shed light on the longitudinal extent of the hemispheric asymmetry. The PRIMO fluxgate magnetometer system includes a dedicated power and data communications platform developed by UNAVCO and successfully operated at ANET stations in the same region. The three PRIMO systems are co-located with existing ANET stations, facilitating logistic efficiencies such as transportation, cross-trained personnel, and common components. Our plan follows recommendations by the latest Heliophysics Decadal Study for ground-based observations, focusing on the American longitudinal sector and leveraging infrastructure through international collaborations.

Long-term vacuum tests of single-mode vertical cavity surface emitting laser diodes used for a scalar magnetometer

NASA Astrophysics Data System (ADS)

Hagen, C.; Ellmeier, M.; Piris, J.; Lammegger, R.; Jernej, I.; Magnes, W.; Murphy, E.; Pollinger, A.; Erd, C.; Baumjohann, W.

2017-11-01

Scalar magnetometers measure the magnitude of the magnetic field, while vector magnetometers (mostly fluxgate magnetometers) produce three-component outputs proportional to the magnitude and the direction of the magnetic field. While scalar magnetometers have a high accuracy, vector magnetometers suffer from parameter drifts and need to be calibrated during flight. In some cases, full science return can only be achieved by a combination of vector and scalar magnetometers.

Data Assimilation Into Physics-Based Models Via Kalman Filters

NASA Astrophysics Data System (ADS)

Schunk, R. W.; Scherliess, L.; Sojka, J. J.

2002-12-01

The magnetosphere-ionosphere-thermosphere (M-I-T) system is a highly dynamic, coupled, and nonlinear system that can vary significantly from hour to hour at any location. The coupling is particularly strong during geomagnetic storms and substorms, but there are appreciable time delays associated with the transfer of mass, momentum, and energy between the domains. Therefore, both global physics-based models and vast observational data sets are needed to elucidate the dynamics, energetics, and coupling in the M-I-T system. Fortunately, during the coming decade, tens of millions of measurements of the global M-I-T system could become available from a variety of in situ and remote sensing instruments. Some of the measurements will provide direct information about the state variables (densities, drift velocities, and temperatures), while others will provide indirect information, such as optical emissions and magnetic perturbations. The data sources available could include: thousands of ground-based GPS Total Electron Content (TEC) receivers; a world-wide network of ionosondes; hundreds of magnetometers both on the ground and in space; occultations from the COSMIC Satellites, numerous ground-based tomography chains; auroral images from the POLAR Satellite; images of the magnetosphere and plasmasphere from the IMAGE Satellite; SuperDARN radar measurements in the polar regions; the Living With a Star (LWS) Solar Dynamics Observatory and the LWS Radiation Belt and Ionosphere-Thermosphere Storm Probes; and the world-wide network of incoherent scatter radars. To optimize the scientific return and to provide specifications and forecasts for societal applications, the global models and data must be combined in an optimum way. A powerful way of assimilating multiple data types into a time-dependent, physics-based, numerical model is via a Kalman filter. The basic principle of this approach is to combine measurements from multiple instrument types with the information obtained from a physics-based model, taking into account the uncertainties in both the model and measurements. The advantages of this technique and the data sources that might be available will be discussed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wedeken, U.; Voelker, H.; Knott, K.

The SSC occurring on March 22, 1979, at 0826 UT had an unusually sharp onset in Scandinavia, in Middle Europe and in experiments on the geostationary satellite GEOS 2, which was near noon, local magnetic time. The ground magnetometer stations showed a small preimpuse which started approx.5 s before the main impulse. Both impulses needed approx.2 s to ''propagate'' from ground stations at L = 6.3-4.6. Search coil magnetometers indicate a very small precursor in northern Finland (Lapprox.4.4-6.0) which started approx.15-20 s before the main impulse. This small precursor also occurred close to the time of the SSC onset atmore » GEOS 2. We interpret this precursor as an effect of precipitating electrons changing the ionospheric conductivity in a localized region. The main impulse triggered damped magnetic pulsations (Psc) with periods near 160 s and 50 s visible in northern Scandinavia and the electric field detector on GEOS 2. Furthermore, the magnetic field and the energetic ions at GEOS observed pulsations with periods near 80 s, but these could only be observed at the northernmost ground stations. There are several indications that the first three harmonics of standing hydromagnetic waves are detected. They may correspond to periodic oscillations of the subsolar point or eigenperiods of the SSC-excited fast mode (compressional cavity resonance). The tentatively identified second harmonic wave (period approx.80 s) is indicative of a bounce resonance of ring current protons. Inside the plasmasphere the dominant period of a superimposed Psc 4 event increased with latitude for the H component indicating several toroidal eigenoscillations.« less

The storm-time equatorial electrojet

NASA Technical Reports Server (NTRS)

Burrows, K.; Sastry, T. S. G.; Sampath, S.; Stolarik, J. D.; Usher, M. J.

1977-01-01

A Petrel rocket carrying a double cell rubidium magnetometer was launched from the Thumba Equatorial Rocket Launching Station during the early main phase of a magnetic storm. No ionospheric currents associated with the storm were observed, and the large field depression at the flight time must therefore be attributed to currents at higher altitudes. The equatorial enhancement of ionospheric magnetic storm currents, predicted on the basis of theory and earlier ground data, was not observed.

The storm-time equatorial electrojet

NASA Technical Reports Server (NTRS)

Burrows, K.; Sastry, T. S. G.; Sampath, S.; Stolarik, J. D.; Usher, M. J.

1976-01-01

A Petrel rocket carrying a double cell rubidium magnetometer was launched from the Thumba Equatorial Rocket Launching Station during the early main phase of a magnetic storm. No ionospheric currents associated with the storm were observed and the large field depression, at the flight time, must therefore be attributed to currents at higher altitudes. The equatorial enhancement of ionospheric magnetic storm currents, predicted on the basis of theory and earlier ground data, was not observed.

Standardized UXO Technology Demonstration Site Open Field Scoring Record No. 908

DTIC Science & Technology

2008-08-01

demonstration at Aberdeen Proving Ground, a system with eight fluxgate magnetometers (Foerster CON650 gradiometers) and RTK-DGPS georeferencing will...be used. The spacing between the individual fluxgate sensors will be 25 cm (ca. 10 inches), totaling to a swath width of 2 m. c. The MAGNETO...MX system consists of: the MX-compact hardware multiplexer electronic module, up to 32 fluxgate gradiometers (for the APG demonstration: 8 fluxgate

Unexploded Ordnance (UXO) Data Analysis System (DAS). Environmental Quality Technology Program

DTIC Science & Technology

2009-09-01

is comprised of an EMI sensor, cesium (Cs) vapor magnetometer , fluxgate magnetometer , hand-held data acquisition computer, integrated power supply...Geometrics model 823A Cs vapor magnetometer . The fluxgate magnetometer is a Bartington model Mag-3MRN60, three- axis fluxgate magnetometer . The system...9. The ERDC hand-held Dual TFM/EMI with ArcSecond positioning system. During standard usage, the fluxgate magnetometer is used to provide the

TRIO (Triplet Ionospheric Observatory) Mission

NASA Astrophysics Data System (ADS)

Lee, D.; Seon, J.; Jin, H.; Kim, K.; Lee, J.; Jang, M.; Pak, S.; Kim, K.; Lin, R. P.; Parks, G. K.; Halekas, J. S.; Larson, D. E.; Eastwood, J. P.; Roelof, E. C.; Horbury, T. S.

2009-12-01

Triplets of identical cubesats will be built to carry out the following scientific objectives: i) multi-observations of ionospheric ENA (Energetic Neutral Atom) imaging, ii) ionospheric signature of suprathermal electrons and ions associated with auroral acceleration as well as electron microbursts, and iii) complementary measurements of magnetic fields for particle data. Each satellite, a cubesat for ion, neutral, electron, and magnetic fields (CINEMA), is equipped with a suprathermal electron, ion, neutral (STEIN) instrument and a 3-axis magnetometer of magnetoresistive sensors. TRIO is developed by three institutes: i) two CINEMA by Kyung Hee University (KHU) under the WCU program, ii) one CINEMA by UC Berkeley under the NSF support, and iii) three magnetometers by Imperial College, respectively. Multi-spacecraft observations in the STEIN instruments will provide i) stereo ENA imaging with a wide angle in local times, which are sensitive to the evolution of ring current phase space distributions, ii) suprathermal electron measurements with narrow spacings, which reveal the differential signature of accelerated electrons driven by Alfven waves and/or double layer formation in the ionosphere between the acceleration region and the aurora, and iii) suprathermal ion precipitation when the storm-time ring current appears. In addition, multi-spacecraft magnetic field measurements in low earth orbits will allow the tracking of the phase fronts of ULF waves, FTEs, and quasi-periodic reconnection events between ground-based magnetometer data and upstream satellite data.

Analysis of ULF Waves During Substorms Observed in the Ionosphere from the Dayside Ground Magnetometer and in the Solar Wind from the Satellite

NASA Astrophysics Data System (ADS)

Streltsov, A. V.; Alimaganbetov, M.

2017-12-01

Magnetospheric substorm is one of the most interesting and complicated phenomena of solar-terrestrial interactions. Despite numerous theoretical and experimental studies conducted during last 50 years, its several important phenomena are not completely understood yet. One of them are intense, ultra-low-frequency (from 0.5 mHz to 100 mHz), electromagnetic pulsations which are always observed during the substorms with the ground-based magnetometers and radars at high latitudes. These waves have the largest amplitudes in the power spectral densities during substorms. Hence, they are the most effective drivers of such mechanisms as high-latitude ionosphere energization, ion outflow production, formation of plasma density cavities, etc. In our study, we focus on the waves with frequencies 0.5-1.0 mHz, which is the lowest part of the frequency spectra observed during the substorm. The questions of what phenomena cause these oscillations and what are their spatiotemporal properties are among the most important ones about the physics of the substorm. To answer these questions, we analyzed disturbances of the magnetic field obtained from the two sources for the period from October 2015 to November 2016 during several substorms. One source is the fluxgate magnetometer in Poker Flat, Alaska. Another is the NASA Advanced Composite Explorer satellite in the Lagrangian L1 point that detects most of the solar wind from the Sun. The goal of our project is to find correlations between the disturbances observed from these sources, which will be a strong argument that the solar wind has a strong influence on the electromagnetic coupling between the ionosphere and magnetosphere of the Earth during the substorms. We observed 48 substorms during the abovementioned period. Our findings show that 1) the dominant frequency of the large-amplitude ULF waves observed during the substorms is 1 mHz or less; and 2) the same frequencies are frequently observed in the waves detected from the both sources. However, there are also some cases of either mismatch of expectation and occurrence of substorm or weak correlation of frequencies. While this work is only focused on 48 events within a year, and utilizes data from a single ground station, it constitutes a firm foundation to investigate theoretical reasoning behind substorm development further.

Methods for Finding Legacy Wells in Large Areas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hammack, Richard; Veloski, Garret; Hodges, D. Greg

More than 10 million wells have been drilled during 150 years of oil and gas production in the United States. When abandoned, many wells were not adequately sealed and now provide a potential conduit for the vertical movement of liquids and gases. Today, groundwater aquifers can be contaminated by surface pollutants flowing down wells or by deep, saline water diffusing upwards. Likewise, natural gas, carbon dioxide (CO 2), or radon can travel upwards via these wells to endanger structures or human health on the surface. Recently, the need to find and plug wells has become critical with the advent ofmore » carbon dioxide injection into geologic formations for enhanced oil recovery (EOR) or carbon storage. The potential for natural gas or brine leakage through existing wells has also been raised as a concern in regions where shale resources are hydraulically fractured for hydrocarbon recovery. In this study, the National Energy Technology Laboratory (NETL) updated existing, effective well finding techniques to be able to survey large areas quickly using helicopter or ground-vehicle-mounted magnetometers, combined with mobile methane detection. For this study, magnetic data were collected using airborne and ground vehicles equipped with two boom-mounted magnetometers, or on foot using a hand-held magnetometer with a single sensor. Data processing techniques were employed to accentuate well-casing-type magnetic signatures. To locate wells with no magnetic signature (wells where the steel well casing had been removed), the team monitored for anomalous concentrations of methane, which could indicate migration of volatile compounds from deeper sedimentary strata along a well or fracture pathway. Methane measurements were obtained using the ALPIS DIfferential Absorption Lidar (DIAL) sensor for helicopter surveys and the Apogee leak detection system (LDS) for ground surveys. These methods were evaluated at a 100-year-old oilfield in Wyoming, where a helicopter magnetic survey accurately located 93% of visible wells. In addition, 20% of the wells found by the survey were previously unknown or inaccurately located. This study found helicopter magnetic surveys to be an accurate, cost- and time-effective means to locate steel-cased wells in large areas, and is a first step in evaluating whether well detection techniques can be applied effectively for well location screening across broad geographic areas.« less

Intra-Inversion Filtering for Use of Magnetic Fields to Locate and Characterize Magnetic Dipoles for Unexploded Ordnance (UXO) Cleanup

DTIC Science & Technology

2007-02-26

IIGE Intra-Inversion Gradient Estimation JPG Jefferson Proving Ground (Indiana); www.jpgbrac.com MTADS Multi- sensor Towed Array Detection...wherein the Statement of Need sought development of algorithms to exploit data from current state-of-the-art geophysical sensors and advanced sensors ...profile direction using an array of magnetometers as in the Multi- sensor Towed Array Detection System (MTADS). In most instances, such data may be

Global Auroral Energy Deposition Compared with Magnetic Indices

NASA Technical Reports Server (NTRS)

Brittnacher, M. J.; Fillingim, M. O.; Elsen, R.; Parks, G. K.; Germany, G. A.; Spann, J. F., Jr.

1997-01-01

Measurement of the global rate of energy deposition in the ionosphere via auroral particle precipitation is one of the primary goals of the Polar UVI program and is an important component of the ISTP program. The instantaneous rate of energy deposition for the entire month of January 1997 has been calculated by applying models to the UVI images and is presented by Fillingim et al. in this session. Magnetic indices, such as Kp, AE, and Dst, which are sensitive to variations in magnetospheric current systems have been constructed from ground magnetometer measurements and employed as measures of activity. The systematic study of global energy deposition raises the possibility of constructing a global magnetospheric activity index explicitly based on particle precipitation to supplement magnetic indices derived from ground magnetometer measurements. The relationship between global magnetic activity as measured by these indices and the rate of total global energy loss due to precipitation is not known at present. We study the correlation of the traditional magnetic index of Kp for the month of January 1997 with the energy deposition derived from the UVI images. We address the question of whether the energy deposition through particle precipitation generally matches the Kp and AE indices, or the more exciting, but distinct, possibility that this particle-derived index may provide an somewhat independent measure of global magnetospheric activity that could supplement traditional magnetically-based activity indices.

10. The surface and interior of venus

USGS Publications Warehouse

Masursky, H.; Kaula, W.M.; McGill, G.E.; Pettengill, G.H.; Phillips, R.J.; Russell, C.T.; Schubert, G.; Shapiro, I.I.

1977-01-01

Present ideas about the surface and interior of Venus are based on data obtained from (1) Earth-based radio and radar: temperature, rotation, shape, and topography; (2) fly-by and orbiting spacecraft: gravity and magnetic fields; and (3) landers: winds, local structure, gamma radiation. Surface features, including large basins, crater-like depressions, and a linear valley, have been recognized from recent ground-based radar images. Pictures of the surface acquired by the USSR's Venera 9 and 10 show abundant boulders and apparent wind erosion. On the Pioneer Venus 1978 Orbiter mission, the radar mapper experiment will determine surface heights, dielectric constant values and small-scale slope values along the sub-orbital track between 50??S and 75??N. This experiment will also estimate the global shape and provide coarse radar images (40-80 km identification resolution) of part of the surface. Gravity data will be obtained by radio tracking. Maps combining radar altimetry with spacecraft and ground-based images will be made. A fluxgate magnetometer will measure the magnetic fields around Venus. The radar and gravity data will provide clues to the level of crustal differentiation and tectonic activity. The magnetometer will determine the field variations accurately. Data from the combined experiments may constrain the dynamo mechanism; if so, a deeper understanding of both Venus and Earth will be gained. ?? 1977 D. Reidel Publishing Company.

The effects of an interplanetary shock on the high-latitude ionospheric convection during an IMF By-dominated period

NASA Astrophysics Data System (ADS)

Coco, I.; Amata, E.; Marcucci, M. F.; Ambrosino, D.; Villain, J.-P.; Hanuise, C.

2008-09-01

On 6 January 1998 an interplanetary shock hit the magnetosphere around 14:15 UT and caused a reconfiguration of the northern high-latitude ionospheric convection. We use SuperDARN, spacecraft and ground magnetometer data to study such reconfiguration. We find that the shock front was tilted towards the morning flank of the magnetosphere, while the Interplanetary Magnetic Field (IMF) was By-dominated, with By<0, IMF Bz>0 and |By|>>Bz. As expected, the magnetospheric compression started at the first impact point of the shock on the magnetopause causing an increase of the Chapman-Ferraro current from dawn to dusk and yielding an increase of the geomagnetic field at the geostationary orbit and on the ground. Moreover, the high-latitude magnetometer data show vortical structures clearly related to the interaction of the shock with the magnetosphere-ionosphere system. In this context, the SuperDARN convection maps show that at very high latitudes above the northern Cusp and in the morning sector, intense sunward convection fluxes appear, well correlated in time with the SI arrival, having a signature typical for Bz>0 dominated lobe reconnection. We suggest that in this case the dynamic pressure increase associated to the shock plays a role in favouring the setting up of a new lobe merging line albeit |By|>>Bz≥0.

Nightside High Latitude Magnetic Impulse Events

NASA Astrophysics Data System (ADS)

Engebretson, M. J.; Connors, M. G.; Braun, D.; Posch, J. L.; Kaur, M.; Guillon, S.; Hartinger, M.; Kim, H.; Behlke, R.; Reiter, K.; Jackel, B. J.; Russell, C. T.

2017-12-01

High latitude Magnetic Impulse Events (MIEs), isolated pulses with periods 5-10 min, were first noted in ground-based magnetometer data near local noon, and are now understood to be signatures of transient pressure increases in the solar wind (sudden impulses - SIs) and/or in the ion foreshock (traveling convection vortex events - TCVs). However, solitary pulses with considerably larger amplitude (ΔB up to 1500 nT) have often been observed in the night sector at these same latitudes. These events are not directly associated with transient external pressure increases, and are often large enough to produce significant ground induced currents. Although many night sector MIEs occur in association with substorm signatures, others appear to be very isolated. We present here a survey of intense MIE events identified in magnetometer data from the AUTUMNX and MACCS arrays in eastern Arctic Canada at all local times between July 1, 2014 and June 30, 2017. We also show maps of horizontal and vertical perturbations and maximum dB/dt values, as well as sample magnetograms, for several example events using data from these and other arrays in Arctic Canada, as well as in West Greenland and Antarctica, the latter to show the conjugate nature of these events. A basic relation to GIC data in the Hydro-Québec electrical transmission network in eastern Canada has been determined and will be discussed.

Optimized merging of search coil and fluxgate data for MMS

NASA Astrophysics Data System (ADS)

Fischer, David; Magnes, Werner; Hagen, Christian; Dors, Ivan; Chutter, Mark W.; Needell, Jerry; Torbert, Roy B.; Le Contel, Olivier; Strangeway, Robert J.; Kubin, Gernot; Valavanoglou, Aris; Plaschke, Ferdinand; Nakamura, Rumi; Mirioni, Laurent; Russell, Christopher T.; Leinweber, Hannes K.; Bromund, Kenneth R.; Le, Guan; Kepko, Lawrence; Anderson, Brian J.; Slavin, James A.; Baumjohann, Wolfgang

2016-11-01

The Magnetospheric Multiscale mission (MMS) targets the characterization of fine-scale current structures in the Earth's tail and magnetopause. The high speed of these structures, when traversing one of the MMS spacecraft, creates magnetic field signatures that cross the sensitive frequency bands of both search coil and fluxgate magnetometers. Higher data quality for analysis of these events can be achieved by combining data from both instrument types and using the frequency bands with best sensitivity and signal-to-noise ratio from both sensors. This can be achieved by a model-based frequency compensation approach which requires the precise knowledge of instrument gain and phase properties. We discuss relevant aspects of the instrument design and the ground calibration activities, describe the model development and explain the application on in-flight data. Finally, we show the precision of this method by comparison of in-flight data. It confirms unity gain and a time difference of less than 100 µs between the different magnetometer instruments.

Multi-Sensor Systems Development for UXO Detection and Discrimination: Hand-Held Dual Magnetic/Electromagnetic Induction Sensor

DTIC Science & Technology

2008-04-01

5 Fluxgate magnetometer ... magnetometer into digital format, and transmitted as a single serial data string to log the Cs and fluxgate magnetometer data. After procurement...Hardware The system hardware comprises an EMI sensor, Cs vapor magnetometer , fluxgate magnetometer , hand-held data acquisition computer, integrated

Complete Tri-Axis Magnetometer Calibration with a Gyro Auxiliary

PubMed Central

Yang, Deng; You, Zheng; Li, Bin; Duan, Wenrui; Yuan, Binwen

2017-01-01

Magnetometers combined with inertial sensors are widely used for orientation estimation, and calibrations are necessary to achieve high accuracy. This paper presents a complete tri-axis magnetometer calibration algorithm with a gyro auxiliary. The magnetic distortions and sensor errors, including the misalignment error between the magnetometer and assembled platform, are compensated after calibration. With the gyro auxiliary, the magnetometer linear interpolation outputs are calculated, and the error parameters are evaluated under linear operations of magnetometer interpolation outputs. The simulation and experiment are performed to illustrate the efficiency of the algorithm. After calibration, the heading errors calculated by magnetometers are reduced to 0.5° (1σ). This calibration algorithm can also be applied to tri-axis accelerometers whose error model is similar to tri-axis magnetometers. PMID:28587115

Trajectory Reconstruction and Uncertainty Analysis Using Mars Science Laboratory Pre-Flight Scale Model Aeroballistic Testing

NASA Technical Reports Server (NTRS)

Lugo, Rafael A.; Tolson, Robert H.; Schoenenberger, Mark

2013-01-01

As part of the Mars Science Laboratory (MSL) trajectory reconstruction effort at NASA Langley Research Center, free-flight aeroballistic experiments of instrumented MSL scale models was conducted at Aberdeen Proving Ground in Maryland. The models carried an inertial measurement unit (IMU) and a flush air data system (FADS) similar to the MSL Entry Atmospheric Data System (MEADS) that provided data types similar to those from the MSL entry. Multiple sources of redundant data were available, including tracking radar and on-board magnetometers. These experimental data enabled the testing and validation of the various tools and methodologies that will be used for MSL trajectory reconstruction. The aerodynamic parameters Mach number, angle of attack, and sideslip angle were estimated using minimum variance with a priori to combine the pressure data and pre-flight computational fluid dynamics (CFD) data. Both linear and non-linear pressure model terms were also estimated for each pressure transducer as a measure of the errors introduced by CFD and transducer calibration. Parameter uncertainties were estimated using a "consider parameters" approach.

Investigation of MAGSAT and TRIAD magnetometer data to provide corrective information on high-lattitude external fields

NASA Technical Reports Server (NTRS)

Potemra, T. A. (Principal Investigator); Sugiura, M.; Zanettic, L. J.

1982-01-01

Disturbances in the MAGSAT magnetometer data set due to high latitude phenomena were evaluated. Much of the categorization of disturbances due to Birkeland currents, ionospheric Hall currents, fine structure and wave phenomena was done with the MAGSAT data catalog. A color graphics technique was developed for the display of disturbances from multiple orbits, from which one can infer a 'global-image' of the current systems of the auroral zone. The MAGSAT 4/81 magnetic field model appears to represent the Earth's main field at high latitudes very well for the epoch 1980. MAGSAT's low altitude allows analysis of disturbances in the magnetometer data due to ionospheric electrojet currents. These current distributions were modeled properly for single events as a precursor to the inference of the Birkeland current system. MAGSAT's orbit was approximately shared with that of the Navy/APL TRIAD satellite. This allowed space-time studies of the magnetic disturbance signatures to be performed, the result being an approximately 75% agreement in, as well as high frequency of, signatures due to Birkeland currents. Thus the field-aligned currents are a steady-state participant in the Earth's magnetospheric current system.

MANGO - A Magnetogram Analysis Service for Enhancement of the Heliophysics Data Environment

NASA Astrophysics Data System (ADS)

Bargatze, L. F.

2011-12-01

The Heliophysics Data Environment Enhancement program supports efforts to integrate data services for conducting research of solar-terrestrial interactions. MANGO, Magnetogram Analysis for the Network of Geophysical Observatories, is a service that is directed at Heliophysics researchers interested in processing magnetic field data from ground magnetometers. Ground magnetograms are essential for monitoring the response of the magnetosphere to solar wind coupling. For instance, it is difficult to understand how spacecraft particle and field variations fit in context of activity throughout the global magnetospheric system without using ground magnetic field data. The MANGO service package allows one to decompose ground magnetic field variations and estimate the relative contributions from secular, diurnal, ring current, and auroral current systems. The MANGO service package leverages the SPASE metadata registries of the Virtual Magnetospheric Observatory (VMO) to compile a list of available magnetogram data products. Currently, MANGO provides access to over 900 data products from about 350 ground magnetic field stations located around the globe. The VMO SPASE Granule registry contains ~150,000 files that comprise the MANGO relevant data products. And, the VMO Granule registry count is steadily increasing as more data products are described and ingested. Data selection from the distributed network of stations is naturally aided by using a world map to display the set of observatories. The MANGO web site (http://mango.igpp.ucla.edu), plots stations on a map that have data products, which meet user-defined criteria based on time of observation, station location, time cadence, magnetometer chain, etc. Note that Many of the ground magnetogram and geomagnetic index data products relevant to the MANGO effort are only available from their data providers in formats that allow the data to be packed. The formats used, and there are many types, save time in file retrieval and space on disk but resulting files require format conversion routines (i.e., from IAGA- 2002, WDC formats to flat ASCII tables) or specialized readers that unpack the desired magnetogram and index data. At present, 408 World Data Center ground magnetic field data products and the ring current Dst index data set have been converted into flat ASCII files, described via SPASE, and registered in the VMO metadata registry as a value-added service to users.

Novel semi-airborne CSEM system for the exploration of mineral resources

NASA Astrophysics Data System (ADS)

Nittinger, Christian; Cherevatova, Maria; Becken, Michael; Rochlitz, Raphael; Günther, Thomas; Martin, Tina; Matzander, Ulrich

2017-04-01

Within the DESMEX project (Deep Electromagnetic Sounding for Mineral Exploration), a semi-airborne CSEM system for mineral exploration is developed which aims to achieve a penetration depth of 1 km with a large areal coverage. Harmonically Time-varying electrical currents are injected with a grounded transmitter in order to measure the electric field on the ground and induced magnetic fields with highly sensitive magnetic sensors in the air. To measure the magnetic field and its variations, three-axis induction coils (MFS-11e by Metronix) and fluxgate sensors (Bartington FGS-03) are mounted on the platform towed by a helicopter. In addition, there is a SQUID based magnetometer, developed by IPHT and Supracon AG, available for future measurements. We deploy the different magnetometer sensors to cover a broad frequency range of 1-10000Hz. During the flight, the sensors encounter a broad variety of motion/vibration which produces noise in the magnetic field sensors. Therefore, a high accuracy motion tracking system is installed within the bird and a low vibrating system design needs to be considered in the airborne sensor platform. We conducted several flights with different source positions in a test area in Germany, which is already covered by ground based measurements. Based on the data, we discuss possible calibration schemes which are needed to overcome orthogonality and scaling errors in the fluxgate data as well as orientation errors. We apply noise correction schemes to the data and calculate transfer functions between the magnetic field and the source current. First 1-D inversion models based on the estimated transfer functions are calculated and compared to existing conductivity models from DC geoelectrics and helicopter electromagnetic (HEM) measurements.

Miniature scientific-grade induction magnetometer for cubesats

NASA Astrophysics Data System (ADS)

Pronenko, Vira

2017-04-01

One of the main areas of space research is the study and forecasting of space weather. The society is more and more depending nowadays on satellite technology and communications, so it is vital to understand the physical process in the solar-terrestrial system which may disturb them. Besides the solar radiation and Space Weather effects, the Earth's ionosphere is also modified by the ever increasing industrial activity. There have been also multiple reports relating VLF and ELF wave activity to atmospheric storms and geological processes, such as earthquakes and volcanic activity. For advancing in these fields, the AC magnetic field permanent monitoring is crucial. Using the cubesat technology would allow increasing the number of measuring points dramatically. It is necessary to mention that the cubesats use for scientific research requires the miniaturization of scientific sensors what is a serious problem because the reduction of their dimensions leads, as a rule, to the parameters degradation, especially of sensitivity threshold. Today, there is no basic model of a sensitive miniature induction magnetometer. Even the smallest one of the known - for the Bepi-Colombo mission to Mercury - is too big for cubesats. The goal of the present report is to introduce the new design of miniature three-component sensor for measurement of alternative vector magnetic fields - induction magnetometer (IM). The study directions were concentrated on the ways and possibilities to create the miniature magnetometer with best combination of parameters. For this a set of scientific and technological problems, mostly aimed at the sensor construction improvement, was solved. The most important parameter characterizing magnetometer quality is its own magnetic noise level (NL). The analysis of the NL influencing factors is made and the ways to decrease it are discussed in the report. Finally, the LEMI-151 IM was developed for the SEAM cubesat mission with optimal performances within the weight and volume constraints. Construction details, tests results and technical specifications of miniature but sensitive IM for cubesat missions are presented. These works were supported by FP7 project #607197 SEAM.

Man-Portable Simultaneous Magnetometer and EM System (MSEMS)

DTIC Science & Technology

2008-12-01

limited to cesium vapor magnetometers outputting a Larmor signal. It cannot, as presently configured, be used with less expensive fluxgate magnetometers ...pulses to convert the frequency-based Larmor signal into nT. A fluxgate magnetometer does not employ the resonance mechanism of an alkali vapor...Simultaneous Magnetometer and EM System (MSEMS) December 2008 Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the

Low Cost, Low Power, High Sensitivity Magnetometer

DTIC Science & Technology

2008-12-01

which are used to measure the small magnetic signals from brain. Other types of vector magnetometers are fluxgate , coil based, and magnetoresistance...concentrator with the magnetometer currently used in Army multimodal sensor systems, the Brown fluxgate . One sees the MEMS fluxgate magnetometer is...Guedes, A.; et al., 2008: Hybrid - LOW COST, LOW POWER, HIGH SENSITIVITY MAGNETOMETER A.S. Edelstein*, James E. Burnette, Greg A. Fischer, M.G

2002 Airborne Geophysical Survey at Pueblo of Laguna Bombing Targets, New Mexico. Revision 3

DTIC Science & Technology

2005-10-01

conducted and results evaluated. The eight cesium magnetometers , GPS systems (positioning and attitude), fluxgate magnetometers , data recording...Accurate positioning requires a correction for this lag. Time lags between the magnetometers , fluxgate magnetometer , and GPS signals were measured by...between magnetometers and fluxgate ); An initial check flight after installation. Under the category of data QA/QC: An extensive test flight to

Analysis of Coordinated Observations in the Region of the Day Side Polar Cleft

DTIC Science & Technology

1988-04-01

measuremrnts in the invariant latitude Reiff. 1982; Luhmann et al., 1984: Chtu et al.. 1985 and range between 70’ and 800 with about 25-min time resolu... light line) .4 L index underneath. (figure courtesy of R. L. McPh! rron). comparison between the measured AL index and the computed AL inJex. The top...This is also a region where irregular magnetic pulsations ular pulsations measured by ground-based magnetometers in often occur. The intensity of these

A Antarctic Magnetometer Chain Along the Cusp Latitude: Preliminary Results

NASA Astrophysics Data System (ADS)

Liu, Y.

2016-12-01

A magnetometer chain from Zhongshan Station to Dome-A in Antarctica has been established since February 2009, consisting in five fluxgate magnetometers, with one regular magnetometer at Zhongshan Station and four low power magnetometers along the cusp latitude in the southern hemisphere, over a distance of 1260 Km. It is one part of the magnetometer network in Antarctic continent, filling the void area for magnetic observation over east-southern Antarctica, greatly enlarging the coverage of the Zhongshan Station. It is also magnetically conjugated with Svalbard region in the Arctic, with a leg extending to DNB in east coast Greenland. Conjunction observation among these magnetometers could provide excellent tracing of series of the typical space physical phenomena such as FTE, TCV, MIE, ULF waves, etc.

The MAVEN Magnetic Field Investigation

NASA Technical Reports Server (NTRS)

Connerney, J. E. P.; Espley, J.; Lawton, P.; Murphy, S.; Odom, J.; Oliversen, R.; Sheppard, D.

2014-01-01

The MAVEN magnetic field investigation is part of a comprehensive particles and fields subsystem that will measure the magnetic and electric fields and plasma environment of Mars and its interaction with the solar wind. The magnetic field instrumentation consists of two independent tri-axial fluxgate magnetometer sensors, remotely mounted at the outer extremity of the two solar arrays on small extensions ("boomlets"). The sensors are controlled by independent and functionally identical electronics assemblies that are integrated within the particles and fields subsystem and draw their power from redundant power supplies within that system. Each magnetometer measures the ambient vector magnetic field over a wide dynamic range (to 65,536 nT per axis) with a quantization uncertainty of 0.008 nT in the most sensitive dynamic range and an accuracy of better than 0.05%. Both magnetometers sample the ambient magnetic field at an intrinsic sample rate of 32 vector samples per second. Telemetry is transferred from each magnetometer to the particles and fields package once per second and subsequently passed to the spacecraft after some reformatting. The magnetic field data volume may be reduced by averaging and decimation, when necessary to meet telemetry allocations, and application of data compression, utilizing a lossless 8-bit differencing scheme. The MAVEN magnetic field experiment may be reconfigured in flight to meet unanticipated needs and is fully hardware redundant. A spacecraft magnetic control program was implemented to provide a magnetically clean environment for the magnetic sensors and the MAVEN mission plan provides for occasional spacecraft maneuvers - multiple rotations about the spacecraft x and z axes - to characterize spacecraft fields and/or instrument offsets in flight.

The MAVEN Magnetic Field Investigation

NASA Astrophysics Data System (ADS)

Connerney, J. E. P.; Espley, J.; Lawton, P.; Murphy, S.; Odom, J.; Oliversen, R.; Sheppard, D.

2015-12-01

The MAVEN magnetic field investigation is part of a comprehensive particles and fields subsystem that will measure the magnetic and electric fields and plasma environment of Mars and its interaction with the solar wind. The magnetic field instrumentation consists of two independent tri-axial fluxgate magnetometer sensors, remotely mounted at the outer extremity of the two solar arrays on small extensions ("boomlets"). The sensors are controlled by independent and functionally identical electronics assemblies that are integrated within the particles and fields subsystem and draw their power from redundant power supplies within that system. Each magnetometer measures the ambient vector magnetic field over a wide dynamic range (to 65,536 nT per axis) with a resolution of 0.008 nT in the most sensitive dynamic range and an accuracy of better than 0.05 %. Both magnetometers sample the ambient magnetic field at an intrinsic sample rate of 32 vector samples per second. Telemetry is transferred from each magnetometer to the particles and fields package once per second and subsequently passed to the spacecraft after some reformatting. The magnetic field data volume may be reduced by averaging and decimation, when necessary to meet telemetry allocations, and application of data compression, utilizing a lossless 8-bit differencing scheme. The MAVEN magnetic field experiment may be reconfigured in flight to meet unanticipated needs and is fully hardware redundant. A spacecraft magnetic control program was implemented to provide a magnetically clean environment for the magnetic sensors and the MAVEN mission plan provides for occasional spacecraft maneuvers—multiple rotations about the spacecraft x and z axes—to characterize spacecraft fields and/or instrument offsets in flight.

Rocket-borne and ground-based measurements in support of the field-widened interferometer experiment - sergeant a30. 276

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ulwick, J.C.; Allred, G.D.; Baker, K.D.

1985-05-28

In April 1983 Utah State University and Air Force Geophysics Laboratory experimenters launched a Sergeant (A30.276) sounding rocket from the Poker Flat Research Range, Alaska. The prime purpose of the flight was to obtain infrared-spectral measurements in the 2-1.5 micrometer m range during an auroral event. In addition to the prime experiment, which has already been reported, the payload contained four photometers, and energy deposition scintillator and an atomic oxygen detector to gather in-situ supporting data. Simultaneously, all-sky television, meridian scanning photometers, riometer, and magnetometers supported the flight from ground-based measuring sites. This report presents a summary of the rocketbornemore » supporting instruments and the data they gathered and provides a time/intensity history of the event as documented by the ground-based meridian scanners and all-sky television.« less

A gamma ray observatory ground attitude error analysis study using the generalized calibration system

NASA Technical Reports Server (NTRS)

Ketchum, E.

1988-01-01

The Goddard Space Flight Center (GSFC) Flight Dynamics Division (FDD) will be responsible for performing ground attitude determination for Gamma Ray Observatory (GRO) support. The study reported in this paper provides the FDD and the GRO project with ground attitude determination error information and illustrates several uses of the Generalized Calibration System (GCS). GCS, an institutional software tool in the FDD, automates the computation of the expected attitude determination uncertainty that a spacecraft will encounter during its mission. The GRO project is particularly interested in the uncertainty in the attitude determination using Sun sensors and a magnetometer when both star trackers are inoperable. In order to examine the expected attitude errors for GRO, a systematic approach was developed including various parametric studies. The approach identifies pertinent parameters and combines them to form a matrix of test runs in GCS. This matrix formed the basis for this study.

Summary of Sessions: Ionosphere - Thermosphere - Mesosphere Working Group

NASA Technical Reports Server (NTRS)

Spann, J. F.; Bhattacharyya, A.

2006-01-01

The topics covered by the sessions under the working group on Ionosphere-Thermosphere-Mesosphere dealt with various aspects of the response of the ionosphere-thermosphere coupled system and the middle atmosphere to solar variability. There were four plenary talks related to the theme of this working group, thirteen oral presentations in three sessions and six poster presentations. A number of issues related to effects of solar variability on the ionosphere-thermosphere, observed using satellite and ground-based data including ground magnetometer observations, radio beacon studies of equatorial spread F, and modeling of some of these effects, were discussed. Radar observations of the mesosphere-lower thermosphere region and a future mission to study the coupling of thunderstorm processes to this region, the ionosphere, and magnetosphere were also presented.

A Merged Dataset for Solar Probe Plus FIELDS Magnetometers

NASA Astrophysics Data System (ADS)

Bowen, T. A.; Dudok de Wit, T.; Bale, S. D.; Revillet, C.; MacDowall, R. J.; Sheppard, D.

2016-12-01

The Solar Probe Plus FIELDS experiment will observe turbulent magnetic fluctuations deep in the inner heliosphere. The FIELDS magnetometer suite implements a set of three magnetometers: two vector DC fluxgate magnetometers (MAGs), sensitive from DC- 100Hz, as well as a vector search coil magnetometer (SCM), sensitive from 10Hz-50kHz. Single axis measurements are additionally made up to 1MHz. To study the full range of observations, we propose merging data from the individual magnetometers into a single dataset. A merged dataset will improve the quality of observations in the range of frequencies observed by both magnetometers ( 10-100 Hz). Here we present updates on the individual MAG and SCM calibrations as well as our results on generating a cross-calibrated and merged dataset.

Evaluating Detection and Estimation Capabilities of Magnetometer-Based Vehicle Sensors

DTIC Science & Technology

2012-05-01

fluxgate magnetometers whose operating characteristics are well documented [1, 2]. Such magnetometers measure two perpendicular magnetic components of...of surveillance scenarios. As part of that work, this analysis focuses on UGS utilizing of two-axis fluxgate magnetometers . Two MOPs are 12 -60 -40 -20...Proceedings of the IEEE, 78(6):973–989, June 1990. [2] E. M. Billingsley and S. W. Billingsley. Fluxgate magnetometers . Proceedings of the IEEE, 5090(194

Feasibility of Using the Space Shuttle to Conduct Global Geomagnetic Surveys (Phase I - Retrievable Probes)

DTIC Science & Technology

1985-07-01

Datatape Division 4-1 5.0 REFERENCES Acuna, M.H. et. al., The MAGSAT Vector Magnetometer - A Precision Fluxgate Magnetometer for the Measurement of the...charting would consist of a triaxial, mutually orthogonal fluxgate magnetometer and an absolute scalar magnetometer to check the flux- gates drift...While space-ready, triaxial fluxgate magnetometers are not an off-the-shelf item, their design concepts are well understood. Their resolution of less

netPICOMAG: a low-cost turn-key magnetometer for aurora detection

NASA Astrophysics Data System (ADS)

Schofield, I.; Connors, M.

2008-12-01

Previous work on development of a compact, low-cost, fluxgate magnetometer, dubbed PICOMAG, yielded a 1-nanotesla resolution, 1-second cadence instrument, suitable for research or teaching solar/terrestrial physics. With a low-cost magnetic instrument and the wider availability of Internet connectivity in the auroral zone (of Canada for example), the potential exists to fill gaps in spatial coverage that still plague auroral geomagnetic research. Thus, the ability to widely distribute accurate, low cost magnetometers was the motivating factor to develop PICOMAG. NetPICOMAG was developed in the effort to refine PICOMAG into a turn-key magnetometer data collection system that is self contained, simple to install and requires zero-maintenance. Once the unit is placed in the ground and connected to the Internet, it locks onto a GPS time signal and begins to transmit magnetic field measurements back to a central data repository, where it is archived, processed and plotted for public viewing via the World Wide Web. It is envisaged (among many other uses) that science teachers can use real scientific data provided by netPICOMAG in teaching the interactions between the sun and the Earth's magnetic field, manifesting itself in the phenomenon known as the northern lights. As such, netPICOMAG can be aptly described and is being promoted as an aurora detector. The netPICOMAG unit is based around three spatially oriented Speake and Company FGM-3/3h series magnetic field sensors that each emit a pulse stream whose frequency is related to the magnetic field along these three axes, and is nearly linearly related to magnetic field perturbations relevant to auroral studies. The individual pulse frequencies are measured by two PIC18F252 programmable microcontrollers. The measurements are combined with a GPS timestamp from a Garmin GPS 18 LVC GPS receiver, and transmitted as plain text as UDP datagrams by a Rabbit Semiconductor RCM4010 8-bit, networked microcontroller module. The self-contained magnetometer unit is encased in a weatherproof 4-inch diameter 3-foot long ABS pipe. It receives power and network over a category 5e cable using a Power-over-Ethernet transmitter/receiver units, permitting it to be stationed as far as 300 feet away from a network access port.

TEC Variations Over Korean Peninsula During Magnetic Storm

NASA Astrophysics Data System (ADS)

Ji, E.-Y.; Choi, B.-K.; Kim, K.-H.; Lee, D.-H.; Cho, J.-H.; Chung, J.-K.; Park, J.-U.

2008-03-01

By analyzing the observations from a number of ground- and space-based instruments, including ionosonde, magnetometers, and ACE interplanetary data, we examine the response of the ionospheric TEC over Korea during 2003 magnetic storms. We found that the variation of vertical TEC is correlated with the southward turning of the interplanetary magnetic field B_z. It is suggested that the electric fields produced by the dynamo process in the high-latitude region and the prompt penetration in the low-latitude region are responsible for TEC increases. During the June 16 event, dayside TEC values increase more than 15%. And the ionospheric F2-layer peak height (hmF2) was ˜300km higher and the vertical E×B drift (estimated from ground-based magnetometer equatorial electrojet delta H) showed downward drift, which may be due to the ionospheric disturbance dynamo electric field produced by the large amount of energy dissipation into high-latitude regions. In contr! ast, during November 20 event, the nightside TEC increases may be due to the prompt penetration westward electric field. The ionospheric F2-layer peak height was below 200km and the vertical E×B drift showed downward drift. Also, a strong correlation is observed between enhanced vertical TEC and enhanced interplanetary electric field. It is shown that, even though TEC increases are caused by the different processes, the electric field disturbances in the ionosphere play an important role in the variation of TEC over Korea.

A phaseonium magnetometer: A new optical magnetometer based on index enhanced media

NASA Technical Reports Server (NTRS)

Scully, Marlan O.; Fleischauer, Michael; Graf, Martin

1993-01-01

An optical magnetometer based on quantum coherence and interference effects in atoms is proposed. The sensitivity of this device is potentially superior to the present state-of-the-art devices. Optimum operating conditions are derived, and a comparison to standard optical pumping magnetometers is made.

Longitudinal Differences of Ionospheric Vertical Density Distribution and Equatorial Electrodynamics

NASA Technical Reports Server (NTRS)

Yizengaw, E.; Zesta, E.; Moldwin, M. B.; Damtie, B.; Mebrahtu, A.; Valledares, C.E.; Pfaff, R. F.

2012-01-01

Accurate estimation of global vertical distribution of ionospheric and plasmaspheric density as a function of local time, season, and magnetic activity is required to improve the operation of space-based navigation and communication systems. The vertical density distribution, especially at low and equatorial latitudes, is governed by the equatorial electrodynamics that produces a vertical driving force. The vertical structure of the equatorial density distribution can be observed by using tomographic reconstruction techniques on ground-based global positioning system (GPS) total electron content (TEC). Similarly, the vertical drift, which is one of the driving mechanisms that govern equatorial electrodynamics and strongly affect the structure and dynamics of the ionosphere in the low/midlatitude region, can be estimated using ground magnetometer observations. We present tomographically reconstructed density distribution and the corresponding vertical drifts at two different longitudes: the East African and west South American sectors. Chains of GPS stations in the east African and west South American longitudinal sectors, covering the equatorial anomaly region of meridian approx. 37 deg and 290 deg E, respectively, are used to reconstruct the vertical density distribution. Similarly, magnetometer sites of African Meridian B-field Education and Research (AMBER) and INTERMAGNET for the east African sector and South American Meridional B-field Array (SAMBA) and Low Latitude Ionospheric Sensor Network (LISN) are used to estimate the vertical drift velocity at two distinct longitudes. The comparison between the reconstructed and Jicamarca Incoherent Scatter Radar (ISR) measured density profiles shows excellent agreement, demonstrating the usefulness of tomographic reconstruction technique in providing the vertical density distribution at different longitudes. Similarly, the comparison between magnetometer estimated vertical drift and other independent drift observation, such as from VEFI onboard Communication/Navigation Outage Forecasting System (C/NOFS) satellite and JULIA radar, is equally promising. The observations at different longitudes suggest that the vertical drift velocities and the vertical density distribution have significant longitudinal differences; especially the equatorial anomaly peaks expand to higher latitudes more in American sector than the African sector, indicating that the vertical drift in the American sector is stronger than the African sector.

Space Technology 5: Pathfinder for Future Micro-Sat Constellations

NASA Technical Reports Server (NTRS)

Carlisle, Candace; Finnegan, Eric

2004-01-01

The Space Technology 5 (ST-5) Project, currently in the implementation phase, is part of the National Aeronautics and Space Administration (NASA) s New Millennium Program (NMP). ST-5 will consist of a constellation of three miniature satellites, each with mass less than 25 kg and size approximately 60 cm by 30 cm. ST-5 addresses technology challenges, as well as fabrication, assembly, test and operations strategies for future micro-satellite missions. ST-5 will be deployed into a highly eccentric, geo-transfer orbit (GTO). This will expose the spacecraft to a high radiation environment as well as provide a low level magnetic background. A three-month flight demonstration phase is planned to validate the technologies and demonstrate concepts for future missions. Each ST-5 spacecraft incorporates NMP competitively-selected breakthrough technologies. These include Cold Gas Micro-Thrusters for propulsion and attitude control, miniature X-band transponder for space-ground communications, Variable Emittance Coatings for dynamic thermal control, and CULPRiT ultra low power logic chip used for Reed-Solomon encoding. The ST-5 spacecraft itself is a technology that can be infused into future missions. It is a fully functional micro-spacecraft built within tight volume and mass constraints. It is built to withstand a high radiation environment, large thermal variations, and high launch loads. The spacecraft power system is low-power and low-voltage, and is designed to turn on after separation &om the launch vehicle. Some of the innovations that are included in the ST-5 design are a custom spacecraft deployment structure, magnetometer deployment boom, nutation damper, X-band antenna, miniature spinning sun sensor, solar array with triple junction solar cells, integral card cage assembly containing single card Command and Data Handling and Power System Electronics, miniature magnetometer, and lithium ion battery. ST-5 will demonstrate the ability of a micro satellite to perform research-quality science. Each ST-5 spacecraft will deploy a precision magnetometer to be used both for attitude determination and as a representative science instrument. The spacecraft has been developed with a low magnetic signature to avoid interference with the magnetometer. The spacecraft will be able to detect and respond autonomously to science events, i.e. significant changes in the magnetic field measurements. The three spacecraft will be a pathfinder for future constellation missions. They will be deployed to demonstrate an appropriate geometry for scientific measurements as a constellation. They will be operationally managed as a constellation, demonstrating automation and communication strategies that will be useful for future missions. The technologies and future mission concepts will be validated both on the ground and in space. Technologies will be validated on the ground by a combination of component level and system level testing of the flight hardware in a thermal vacuum environment. In flight, specific validation runs are planned for each of the technologies. Each validation run consists of one or more orbits with a specific validation objective. This paper will describe the ST-5 mission, and the applicability of the NMP technologies, spacecraft, and mission concepts to future missions. It will also discuss the validation approach for the ST-5 technologies and mission concepts.

An explanation of auroral intensification during the substorm expansion phase

NASA Astrophysics Data System (ADS)

Yao, Zhonghua; Rae, I. J.; Lui, A. T. Y.; Murphy, K. R.; Owen, C. J.; Pu, Z. Y.; Forsyth, C.; Grodent, D.; Zong, Q.-G.; Du, A. M.; Kalmoni, N. M. E.

2017-08-01

A multiple auroral onset substorm on 28 March 2010 provides an opportunity to understand the physical mechanism in generating auroral intensifications during a substorm expansion phase. Conjugate observations of magnetic fields and plasma from the Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft, of field-aligned currents (FACs) from the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) satellites, and from ground-based magnetometers and aurora are all available. The comprehensive measurements allow us to further our understanding of the complicated causalities among dipolarization, FAC generation, particle acceleration, and auroral intensification. During the substorm expansion phase, the plasma sheet expanded and was perturbed leading to the generation of a slow mode wave, which modulated electron flux in the outer plasma sheet. During this current sheet expansion, field-aligned currents formed, and geomagnetic perturbations were simultaneously detected by ground-based instruments. However, a magnetic dipolarization did not occur until about 3 min later in the outer plasma sheet observed by THEMIS-A spacecraft (THA). We believe that this dipolarization led to an efficient Fermi acceleration to electrons and consequently the cause of a significant auroral intensification during the expansion phase as observed by the All-Sky Imagers (ASIs). This Fermi acceleration mechanism operating efficiently in the outer plasma sheet during the expansion phase could be a common explanation of the poleward auroral development after substorm onset. These results also show a good agreement between the upward FAC derived from AMPERE measurements and the auroral brightening observed by the ASIs.

Electron-Tunneling Magnetometer

NASA Technical Reports Server (NTRS)

Kaiser, William J.; Kenny, Thomas W.; Waltman, Steven B.

1993-01-01

Electron-tunneling magnetometer is conceptual solid-state device operating at room temperature, yet offers sensitivity comparable to state-of-art magnetometers such as flux gates, search coils, and optically pumped magnetometers, with greatly reduced volume, power consumption, electronics requirements, and manufacturing cost. Micromachined from silicon wafer, and uses tunneling displacement transducer to detect magnetic forces on cantilever-supported current loop.

Calibration of a fluxgate magnetometer array and its application in magnetic object localization

NASA Astrophysics Data System (ADS)

Pang, Hongfeng; Luo, Shitu; Zhang, Qi; Li, Ji; Chen, Dixiang; Pan, Mengchun; Luo, Feilu

2013-07-01

The magnetometer array is effective for magnetic object detection and localization. Calibration is important to improve the accuracy of the magnetometer array. A magnetic sensor array built with four three-axis DM-050 fluxgate magnetometers is designed, which is connected by a cross aluminum frame. In order to improve the accuracy of the magnetometer array, a calibration process is presented. The calibration process includes magnetometer calibration, coordinate transformation and misalignment calibration. The calibration system consists of a magnetic sensor array, a GSM-19T proton magnetometer, a two-dimensional nonmagnetic rotation platform, a 12 V-dc portable power device and two portable computers. After magnetometer calibration, the RMS error has been decreased from an original value of 125.559 nT to a final value of 1.711 nT (a factor of 74). After alignment, the RMS error of misalignment has been decreased from 1322.3 to 6.0 nT (a factor of 220). Then, the calibrated array deployed on the nonmagnetic rotation platform is used for ferromagnetic object localization. Experimental results show that the estimated errors of X, Y and Z axes are -0.049 m, 0.008 m and 0.025 m, respectively. Thus, the magnetometer array is effective for magnetic object detection and localization in three dimensions.

Choice of Magnetometers and Gradiometers after Signal Space Separation.

PubMed

Garcés, Pilar; López-Sanz, David; Maestú, Fernando; Pereda, Ernesto

2017-12-16

Modern Elekta Neuromag MEG devices include 102 sensor triplets containing one magnetometer and two planar gradiometers. The first processing step is often a signal space separation (SSS), which provides a powerful noise reduction. A question commonly raised by researchers and reviewers relates to which data should be employed in analyses: (1) magnetometers only, (2) gradiometers only, (3) magnetometers and gradiometers together. The MEG community is currently divided with regard to the proper answer. First, we provide theoretical evidence that both gradiometers and magnetometers result from the backprojection of the same SSS components. Then, we compare resting state and task-related sensor and source estimations from magnetometers and gradiometers in real MEG recordings before and after SSS. SSS introduced a strong increase in the similarity between source time series derived from magnetometers and gradiometers (r² = 0.3-0.8 before SSS and r² > 0.80 after SSS). After SSS, resting state power spectrum and functional connectivity, as well as visual evoked responses, derived from both magnetometers and gradiometers were highly similar (Intraclass Correlation Coefficient > 0.8, r² > 0.8). After SSS, magnetometer and gradiometer data are estimated from a single set of SSS components (usually ≤ 80). Equivalent results can be obtained with both sensor types in typical MEG experiments.

An initial investigation of the long-term trends in the fluxgate magnetometer (FGM) calibration parameters on the four Cluster spacecraft

NASA Astrophysics Data System (ADS)

Alconcel, L. N. S.; Fox, P.; Brown, P.; Oddy, T. M.; Lucek, E. L.; Carr, C. M.

2014-07-01

Over the course of more than 10 years in operation, the calibration parameters of the outboard fluxgate magnetometer (FGM) sensors on the four Cluster spacecraft are shown to be remarkably stable. The parameters are refined on the ground during the rigorous FGM calibration process performed for the Cluster Active Archive (CAA). Fluctuations in some parameters show some correlation with trends in the sensor temperature (orbit position). The parameters, particularly the offsets, of the spacecraft 1 (C1) sensor have undergone more long-term drift than those of the other spacecraft (C2, C3 and C4) sensors. Some potentially anomalous calibration parameters have been identified and will require further investigation in future. However, the observed long-term stability demonstrated in this initial study gives confidence in the accuracy of the Cluster magnetic field data. For the most sensitive ranges of the FGM instrument, the offset drift is typically 0.2 nT per year in each sensor on C1 and negligible on C2, C3 and C4.

An initial investigation of the long-term trends in the fluxgate magnetometer (FGM) calibration parameters on the four Cluster spacecraft

NASA Astrophysics Data System (ADS)

Alconcel, L. N. S.; Fox, P.; Brown, P.; Oddy, T. M.; Lucek, E. L.; Carr, C. M.

2014-01-01

Over the course of more than ten years in operation, the calibration parameters of the outboard fluxgate magnetometer (FGM) sensors on the four Cluster spacecraft are shown to be remarkably stable. The parameters are refined on the ground during the rigorous FGM calibration process performed for the Cluster Active Archive (CAA). Fluctuations in some parameters show some correlation with trends in the sensor temperature (orbit position). The parameters, particularly the offsets, of the Spacecraft1 (C1) sensor have undergone more long-term drift than those of the other spacecraft (C2, C3 and C4) sensors. Some potentially anomalous calibration parameters have been identified and will require further investigation in future. However, the observed long-term stability demonstrated in this initial study gives confidence in the relative accuracy of the Cluster magnetic field data. For the most sensitive ranges of the FGM instrument, the offset drift is typically 0.2 nT yr-1 in each sensor on C1 and negligible on C2, C3 and C4.

Observations of ionospheric convection vortices - Signatures of momentum transfer

NASA Technical Reports Server (NTRS)

Mchenry, M. A.; Clauer, C. R.; Friis-Christensen, E.; Kelly, J. D.

1988-01-01

Several classes of traveling vortices in the dayside ionospheric flow have been detected and tracked using the Greenland magnetometer chain. One class observed during quiet times consists of a continuous series of vortices moving generally antisunward for several hours at a time. Assuming each vortex to be the convection pattern produced by a small field aligned current moving across the ionosphere, the amount of field aligned current was found by fitting a modeled ground magnetic signature to measurements from the chain of magnetometers. The calculated field aligned current is seen to be steady for each vortex and neighboring vortices have currents of opposite sign. Low altitude DMSP observations indicate the vortices are on field lines which map to the inner edge of the low latitude boundary layer. Because the vortices are conjugate to the boundary layer, repeat in a regular fashion and travel antisunward, it is argued that this class of vortices is caused by surface waves at the magnetopause. No strong correlations between field aligned current strength and solar wind density, velocity, or Bz is found.

Improved Modeling in a Matlab-Based Navigation System

NASA Technical Reports Server (NTRS)

Deutschmann, Julie; Bar-Itzhack, Itzhack; Harman, Rick; Larimore, Wallace E.

1999-01-01

An innovative approach to autonomous navigation is available for low earth orbit satellites. The system is developed in Matlab and utilizes an Extended Kalman Filter (EKF) to estimate the attitude and trajectory based on spacecraft magnetometer and gyro data. Preliminary tests of the system with real spacecraft data from the Rossi X-Ray Timing Explorer Satellite (RXTE) indicate the existence of unmodeled errors in the magnetometer data. Incorporating into the EKF a statistical model that describes the colored component of the effective measurement of the magnetic field vector could improve the accuracy of the trajectory and attitude estimates and also improve the convergence time. This model is identified as a first order Markov process. With the addition of the model, the EKF attempts to identify the non-white components of the noise allowing for more accurate estimation of the original state vector, i.e. the orbital elements and the attitude. Working in Matlab allows for easy incorporation of new models into the EKF and the resulting navigation system is generic and can easily be applied to future missions resulting in an alternative in onboard or ground-based navigation.

Structural Bus and Release Mechanisms on the ST5 Satellites: Summary and Status

NASA Technical Reports Server (NTRS)

Rossoni, Peter

2007-01-01

The Space Technology 5 Mechanical System met the challenge of packaging a fully functional science and technology satellite system with its Deployer mechanism into a compact 0.07cu m volume. Three 25 kg satellites were orbited in constellation in March, 2006. The ST5 mechanical system is composed of 1) The Structural Bus; 2) Magnetometer Instrument Boom 3) Spacecraft Deployer Release Mechanism This system includes a highly integrated electronics enclosure as a multifunctional structure; a lightweight, magnetically clean Magnetometer Boom; the first use of Nitinol Shape-Memory Alloy trigger devices for deploying multiple spacecraft; an innovative compliant mount for the umbilical connector and a Deployer mechanism that imparts both separation velocity and mission spin rate to three constellation flying satellites These elements employed cutting-edge design and analysis tools, state-of-the-art testing facilities and proven engineering techniques to meet stringent performance criteria, enabling the mission s success.

Optical Magnetometry using Multipass Cells with overlapping beams

NASA Astrophysics Data System (ADS)

McDonough, Nathaniel David; Lucivero, Vito Giovanni; Dural, Nezih; Romalis, Michael

2017-04-01

In recent years, multipass cells with cylindrical mirrors have proven to be a successful way of making highly sensitive atomic magnetometers. In such cells a small laser beam makes 40 to 100 passes within the cell without significant overlap with itself. Here we describe a new multi-pass geometry which uses spherical mirrors to reflect the probe beam multiple times over the same cell region. Such geometry reduces the effects of atomic diffusion while preserving the advantages of multi-pass cells over standing-wave cavities, namely a deterministic number of passes and absence of interference. We have fabricated several cells with this geometry and obtained good agreement between the measured and calculated levels of quantum spin noise. We will report on our effort to characterize the diffusion spin-correlation function in these cells and operation of the cell as a magnetometer. This work is supported by DARPA.

Monitoring Space Weather Hazards caused by geomagnetic disturbances with Space Hazard Monitor (SHM) systems

NASA Astrophysics Data System (ADS)

Xu, Z.; Gannon, J. L.; Peek, T. A.; Lin, D.

2017-12-01

One space weather hazard is the Geomagnetically Induced Currents (GICs) in the electric power transmission systems, which is naturally induced geoelectric field during the geomagnetic disturbances (GMDs). GICs are a potentially catastrophic threat to bulk power systems. For instance, the Blackout in Quebec in March 1989 was caused by GMDs during a significant magnetic storm. To monitor the GMDs, the autonomous Space Hazard Monitor (SHM) system is developed recently. The system includes magnetic field measurement from magnetometers and geomagnetic field measurement from electrodes. In this presentation, we introduce the six sites of SHMs which have been deployed in the US continental regions. The data from the magnetometers are processed with the Multiple Observatory Geomagnetic Data Analysis Software (MOGDAS). And the statistical results are presented here. It reveals not only the impacts of space weather over US continental region but also the potential of improving instrumentation development to provide better space weather monitor.

Data Collection and Analysis for Personnel Detection at a Border Crossing

DTIC Science & Technology

2011-01-01

3 Figure 4. Picture of fluxgate magnetometer ...materials carried by people, e.g., keys, firearms, and knives. For the experiment we used Model 1540 three-axis fluxgate magnetometers from Applied... magnetometer were collected at 10 samples per second. Figure 4 shows a photo of the emplaced fluxgate magnetometer . 4 Figure 4. Picture of fluxgate

Method of performing MRI with an atomic magnetometer

DOEpatents

Savukov, Igor Mykhaylovich; Matlashov, Andrei Nikolaevich; Espy, Michelle A.; Volegov, Petr Lvovich; Kraus, Jr., Robert Henry; Zotev, Vadim Sergeyevich

2012-11-06

A method and apparatus are provided for performing an in-situ magnetic resonance imaging of an object. The method includes the steps of providing an atomic magnetometer, coupling a magnetic field generated by magnetically resonating samples of the object through a flux transformer to the atomic magnetometer and measuring a magnetic resonance of the atomic magnetometer.

Method of performing MRI with an atomic magnetometer

DOEpatents

Savukov, Igor Mykhaylovich; Matlashov, Andrei Nikolaevich; Espy, Michelle A; Volegov, Petr Lvovich; Kraus, Jr., Robert Henry; Zotev, Vadim Sergeyevich

2013-08-27

A method and apparatus are provided for performing an in-situ magnetic resonance imaging of an object. The method includes the steps of providing an atomic magnetometer, coupling a magnetic field generated by magnetically resonating samples of the object through a flux transformer to the atomic magnetometer and measuring a magnetic resonance of the atomic magnetometer.

Response of a Bell–Bloom Magnetometer to a Magnetic Field of Arbitrary Direction

PubMed Central

Ding, Zhichao; Yuan, Jie; Long, Xingwu

2018-01-01

The Bell–Bloom magnetometer in response to a magnetic field of arbitrary direction is observed theoretically and experimentally. A theoretical model is built from a macroscopic view to simulate the magnetometer frequency response to an external magnetic field of arbitrary direction. Based on the simulation results, the magnetometer characteristics, including the signal phase and amplitude at resonance, the linewidth, and the magnetometer sensitivity, are analyzed, and the dependencies of these characteristics on the external magnetic field direction are obtained, which are verified by the experiment. PMID:29724059

Testing electrostatic equilibrium in the ionosphere by detailed comparison of ground magnetic deflection and incoherent scatter radar.

NASA Astrophysics Data System (ADS)

Cosgrove, R. B.; Schultz, A.; Imamura, N.

2016-12-01

Although electrostatic equilibrium is always assumed in the ionosphere, there is no good theoretical or experimental justification for the assumption. In fact, recent theoretical investigations suggest that the electrostatic assumption may be grossly in error. If true, many commonly used modeling methods are placed in doubt. For example, the accepted method for calculating ionospheric conductance??field line integration??may be invalid. In this talk we briefly outline the theoretical research that places the electrostatic assumption in doubt, and then describe how comparison of ground magnetic field data with incoherent scatter radar (ISR) data can be used to test the electrostatic assumption in the ionosphere. We describe a recent experiment conducted for the purpose, where an array of magnetometers was temporalily installed under the Poker Flat AMISR.

On the origin of the Bangui magnetic anomaly, central African empire

NASA Technical Reports Server (NTRS)

Marsh, B. D.

1977-01-01

A large magnetic anomaly was recognized in satellite magnetometer data over the Central African Empire in central Africa. They named this anomaly the Bangui magnetic anomaly due to its location near the capital city of Bangui, C.A.E. Because large crustal magnetic anomalies are uncommon, the origin of this anomaly has provoked some interest. The area of the anomaly was visited to make ground magnetic measurements, geologic observations, and in-situ magnetic susceptibility measurements. Some rock samples were also collected and chemically analyzed. The results of these investigations are presented.

Substorm injection boundaries. [magnetospheric electric field model

NASA Technical Reports Server (NTRS)

Mcilwain, C. E.

1974-01-01

An improved magnetospheric electric field model is used to compute the initial locations of particles injected by several substorms. Trajectories are traced from the time of their encounter with the ATS-5 satellite backwards to the onset time given by ground-based magnetometers. A spiral shaped inner boundary of injection is found which is quite similar to that found by a statistical analysis. This injection boundary is shown to move in an energy dependent fashion which can explain the soft energy spectra observed at the inner edge of the electrons plasma sheet.

The polarization and the fundamental sensitivity of 39K (133Cs)-85Rb-4He hybrid optical pumping spin exchange relaxation free atomic magnetometers.

PubMed

Liu, Jian-Hua; Jing, Dong-Yang; Wang, Liang-Liang; Li, Yang; Quan, Wei; Fang, Jian-Cheng; Liu, Wu-Ming

2017-07-28

The hybrid optical pumping spin exchange relaxation free (SERF) atomic magnetometers can realize ultrahigh sensitivity measurement of magnetic field and inertia. We have studied the 85 Rb polarization of two types of hybrid optical pumping SERF magnetometers based on 39 K- 85 Rb- 4 He and 133 Cs- 85 Rb- 4 He respectively. Then we found that 85 Rb polarization varies with the number density of buffer gas 4 He and quench gas N 2 , pumping rate of pump beam and cell temperature respectively, which will provide an experimental guide for the design of the magnetometer. We obtain a general formula on the fundamental sensitivity of the hybrid optical pumping SERF magnetometer due to shot-noise. The formula describes that the fundamental sensitivity of the magnetometer varies with the number density of buffer gas and quench gas, the pumping rate of pump beam, external magnetic field, cell effective radius, measurement volume, cell temperature and measurement time. We obtain a highest fundamental sensitivity of 1.5073 aT/Hz 1/2 (1 aT = 10 -18 T) with 39 K- 85 Rb- 4 He magnetometer between above two types of magnetometers when 85 Rb polarization is 0.1116. We estimate the fundamental sensitivity limit of the hybrid optical pumping SERF magnetometer to be superior to 1.8359 × 10 -2 aT/Hz 1/2 , which is higher than the shot-noise-limited sensitivity of 1 aT/Hz 1/2 of K SERF atomic magnetometer.

Standardized UXO Technology Demonstration Site Blind Grid Scoring Record No. 806 (U.S. Geological Survey, TMGS Magnetometer/Towed Array)

DTIC Science & Technology

2007-05-01

BOX 25046, FEDERAL CENTER, M.S. 964 DENVER, CO 80225-0046 TECHNOLOGY TYPE/PLATFORM: TMGS MAGNETOMETER/TOWED ARRAY PREPARED BY: U.S. ARMY...GEOLOGICAL SURVEY, TMGS MAGNETOMETER/TOWED ARRAY) 8-CO-160-UXO-021 Karwatka, Michael... TMGS Magnetometer/Towed Array, MEC Unclassified Unclassified Unclassified SAR (Page ii Blank) i ACKNOWLEDGMENTS

Lunar surface magnetometers

NASA Technical Reports Server (NTRS)

Dyal, P.; Gordon, D. I.

1973-01-01

Discussion of the properties of both the stationary and portable magnetometers used in the Apollo program to measure static and dynamic fields on the lunar surface. A stationary magnetometer is described in which the three orthogonal vector components of the magnetic field are measured by three fluxgate sensors which are located at the ends of three orthogonal booms and contain ferromagnetic cores driven to saturation by means of a periodic current. In the Apollo 16 magnetometer special high-stability ring-core sensors were used which provided an output voltage to the analog-to-digital converter which is proportional to the magnetic field. A portable magnetometer is described which consists of a set of three orthogonal fluxgate sensors mounted on top of a tripod connected to an electronics box by a ribbon cable. The above-mentioned stationary magnetometer simultaneously measured the time-varying components of the field which were later subtracted from the portable magnetometer measurements to give the desired resultant steady field values caused by the magnetized crustal material.

The Thing We Really Need

NASA Astrophysics Data System (ADS)

Donovan, E.

2017-12-01

I'm known for hyperbole and provocative statements. "What do you get from 10,000 magnetometers distributed around the globe? A low resolution image of currents." To a great extent, I'm having fun with such statements, I truly value the phenomenal armada of spacecraft - the HSO - with which we are exploring geospace, and certainly we need the in situ measurements to unravel the fundamental (small scale) processes at the heart of space weather. But, for me there is underlying truth for my light-hearted rhetoric. The geospace community has been too accepting of arguments against significant investment in imaging. Some say "you can't do science with images." My answer? "Tell that to the astronomers". Some say "we've flown an auroral imager… been there, done that." My answer? "The fact that we've flown ten magnetometers seems to not preclude flying another ten." We are comfortable spending multiple billions of dollars on in situ observations, yet uncomfortable spending even just tens of millions on imaging. Why does this matter? In situ focused missions are giving us a profoundly important of the small scale physics by which everything in geospace happens. However, these effects spin up via space/time scales that are poorly sampled. We are often left piecing together the critically important mesoscale picture with dramatically under-sampled "images". Consider the images below. Consider the SDO images showing a flare in exquisite detail in multiple wavelengths. With these, solar physicists have made dramatic advances relating small scale with mesoscales and their consequences. Through these the public has been inspired and awe stricken. Consider the ASI images with overlaid SuperDARN observations. Such images have allowed us to make great advances, but it's time for us to acknowledge that our imaging leaves too much to the imagination, and falls well short of creating visuals that inspire. It's time for us to make the movie of our system. In this presentation, I suggest a $3B "mission to geospace" with three pillars: (1) a continent-size ground-based network of innovative new instruments; (2) four satellites on Molniya orbits outfitted with next-generation multi-wavelength optical, ENA and X-Ray imagers; and (3) 100 satellites in formation in the magnetosphere providing radio sounding and in situ observations of key regions.

Goddard Space Flight Center Spacecraft Magnetic Test Facility Restoration Project

NASA Technical Reports Server (NTRS)

Vernier, Robert; Bonalksy, Todd; Slavin, James

2004-01-01

The Goddard Space Flight Center Spacecraft Magnetic Test Facility (SMTF) was constructed in the 1960's for the purpose of simulating geomagnetic and interplanetary magnetic field environments. The facility includes a three axis Braunbek coil system consisting of 12 loops, 4 loops on each of the three orthogonal axes; a remote Earth field sensing magnetometer and servo controller; and a remote power control and instrumentation building. The inner coils of the Braunbek system are 42-foot in diameter with a 10-foot by 10-foot opening through the outer coils to accommodate spacecraft access into the test volume. The physical size and precision of the facility are matched by only two other such facilities in the world. The facility was used extensively from the late 1960's until the early 1990's when the requirement for spacecraft level testing diminished. New NASA missions planned under the Living with a Star, Solar Terrestrial Probes, Explorer, and New Millennium Programs include precision, high-resolution magnetometers to obtain magnetic field data that is critical to fulfilling their scientific mission. It is highly likely that future Lunar and Martian exploration missions will also use precision magnetometers to conduct geophysical magnetic surveys. To ensure the success of these missions, ground-testing using a magnetic test facility such as the GSFC SMTF will be required. This paper describes the history of the facility, the future mission requirements that have renewed the need for spacecraft level magnetic testing, and the plans for restoring the facility to be capable of performing to its original design specifications.

Goddard Space Flight Center Spacecraft Magnetic Test Facility Restoration Project

NASA Technical Reports Server (NTRS)

Vernier, Robert; Bonalosky, Todd; Slavin, James

2004-01-01

The Goddard Space Flight Center Spacecraft Magnetic Test Facility (SMTF) was constructed in the 1960's for the purpose of simulating geomagnetic and interplanetary magnetic field environments. The facility includes a three axis Braunbek coil system consisting of 12 loops, 4 loops on each of the three orthogonal axes; a remote Earth field sensing magnetometer and servo controller; and a remote power control and instrumentation building. The inner coils of the Braunbek system are 42-foot in diameter with a 10-foot by 10-foot opening through the outer coils to accommodate spacecraft access into the test volume. The physical size and precision of the facility are matched by only two other such facilities in the world. The facility was used extensively from the late 1960's until the early 1990's when the requirement for spacecraft level testing diminished. New NASA missions planned under the Living with a Star, Solar Terrestrial Probes, Explorer, and New Millennium Programs include precision, high-resolution magnetometers to obtain magnetic field data that is critical to fulfilling their scientific mission. It is highly likely that future Lunar and Martian exploration missions will also use precision magnetometers to conduct geophysical magnetic surveys. To ensure the success of these missions, ground testing using a magnetic test facility such as the GSFC SMTF will be required. This paper describes the history of the facility, the future mission requirements that have renewed the need for spacecraft level magnetic testing, and the plans for restoring the facility to be capable of performing to its original design specifications.

Fabrication of Superconducting Quantum Interference Device Magnetometers on a Glass Epoxy Polyimide Resin Substrate with Copper Terminals

NASA Astrophysics Data System (ADS)

Kawai, Jun; Kawabata, Miki; Oyama, Daisuke; Uehara, Gen

We have developed fabrication technique of superconducting quantum interference device (SQUID) magnetometers based on Nb/AlAlOx/Nb junctions directly on a glass epoxy polyimide resin substrate, which has copper terminals embedded in advance. The advantage of this method is that no additional substrate and wirebonds are needed for assembly. Compared to conventional SQUID magnetometers, which are assembled with a SQUID chip fabricated on a Si substrate and wirebonding technique, low risk of disconnection can be expected. A directly-coupled multi-loop SQUID magnetometer fabricated with this method has as good noise performance as a SQUID magnetometer with the same design fabricated on a Si wafer. The magnetometer sustained its performance through thermal cycle test 13 times so far.

The MASCOT Magnetometer

NASA Astrophysics Data System (ADS)

Herčík, David; Auster, Hans-Ulrich; Blum, Jürgen; Fornaçon, Karl-Heinz; Fujimoto, Masaki; Gebauer, Kathrin; Güttler, Carsten; Hillenmaier, Olaf; Hördt, Andreas; Liebert, Evelyn; Matsuoka, Ayako; Nomura, Reiko; Richter, Ingo; Stoll, Bernd; Weiss, Benjamin P.; Glassmeier, Karl-Heinz

2017-07-01

The Mobile Asteroid Scout (MASCOT) is a small lander on board the Hayabusa2 mission of the Japan Aerospace Exploration Agency to the asteroid 162173 Ryugu. Among the instruments on MASCOT is a fluxgate magnetometer, the MASCOT Magnetometer (MasMag). The magnetometer is a lightweight (˜280 g) and low power (˜0.5 W) triaxial fluxgate magnetometer. Magnetic field measurements during the landing period and during the surface operational phase shall provide information about any intrinsic magnetic field of the asteroid and its remanent magnetization. This could provide important constraints on planet formation and the thermal and aqueous evolution of primitive asteroids.

Geomagnetic referencing--the real-time compass for directional drillers

USGS Publications Warehouse

Buchanan, Andrew; Finn, Carol; Love, Jeffrey J.; Worthington, E. William; Lawson, Fraser; Maus, Stefan; Okewunmi, Shola; Poedjono, Benny

2013-01-01

To pinpoint the location and direction of a wellborne, directional driller rely on measurements from accelerometers, magnetometer and gyroscopes. In the past, high-accuracy guidance methods required a halt in drilling to obtain directional measurements. Advances in geomagnetic referencing now allow companies to use real-time data acquired during drilling to accurately potion horizontal wells, decrease well spacing and drill multiple wells from limited surface locations.

Dayside ionospheric convection changes in response to long-period interplanetary magnetic field oscillations - Determination of the ionospheric phase velocity

NASA Technical Reports Server (NTRS)

Saunders, M. A.; Freeman, M. P.; Southwood, D. J.; Cowley, S. W.; Lockwood, M.; Samson, J. C.; Farrugia, C. J.; Hughes, T. J.

1992-01-01

Ground magnetic field perturbations recorded by the CANOPUS magnetometer network in the 7 to 13 MLT sector are used to examine how reconfigurations of the dayside polar ionospheric flow take place in response to north-south changes of the IMF. During the 6-h interval in question, IMF Bz oscillates between +/- 7 nT with about a 1-h period. Corresponding variations in the ground magnetic disturbance are observed which we infer are due to changes in ionospheric flow. Cross correlation of the data obtained from two ground stations at 73.5 deg magnetic latitude, but separated by about 2 hours in MLT, shows that changes in the flow are initiated in the prenoon sector (about 10 MLT) and then spread outward toward dawn and dusk with a phase speed of about 5 km/s over the longitude range about 8 to 12 MLT, slowing to about 2 km/s outside this range. Cross correlating the data from these ground stations with IMP 8 IMF Bz records produces a MLT variation in the ground response delay relative to the IMF which is compatible with these deduced phase speeds.

Development of a Micro-Fabricated Total-Field Magnetometer

DTIC Science & Technology

2011-03-01

are made with fluxgate technologies. Fluxgates have lower sensitivity than Cs magnetometers , yet they continue to be used in small wands simply...extraction process by providing the sensitivity of a Cs magnetometer with the convenience and low cost of a fluxgate wand. Extremely small and low cost...FINAL REPORT Development of a Micro-Fabricated Total-Field Magnetometer SERDP Project MR-1512 MARCH 2011 Mark Prouty Geometrics, Inc

The DMSP Space Weather Sensors Data Archive Listing (1982-2013) and File Formats Descriptions

DTIC Science & Technology

2014-08-01

environment sensors including the auroral particle spectrometer (SSJ), the fluxgate magnetometer (SSM), the topside thermal plasma monitor (SSIES... Fluxgate Magnetometer (SSM) for the Defense Meteorological Satellite Program (DMSP) Block 5D-2, Flight 7, Instrument Papers, AFGL-TR-84-0225; ADA155229...Flux) SSM The fluxgate magnetometer . (Special Sensor, Magnetometer ) SSULI The ultraviolet limb imager SSUSI The ultraviolet spectrographic imager

Demonstration of an Enhanced Vertical Magnetic Gradient System for UXO

DTIC Science & Technology

2008-04-01

flights were conducted and results evaluated. The cesium magnetometers , GPS systems (positioning and attitude), fluxgate magnetometers , data...makes a measurement and when it is time-stamped and recorded. This applies to the magnetometers , fluxgate and the GPS. Accurate positioning...requires a correction for this lag. Time lags between the magnetometers , fluxgate and GPS signals were measured by a proprietary utility. This utility

Man-Portable Simultaneous Magnetometer and EM System (MSEMS)

DTIC Science & Technology

2008-12-01

expensive fluxgate magnetometers . This is because the interleaving hardware is expecting a Larmor signal as input; it performs period counting of the...Larmor signal between EM61 pulses to convert the frequency-based Larmor signal into nanotesla. A fluxgate magnetometer does not employ the resonance...FINAL REPORT Man-Portable Simultaneous Magnetometer and EM System (MSEMS) ESTCP Project MM-0414 December 2008 Robert Siegel Science

Vector Fluxgate Magnetometer (VMAG) Development for DSX

DTIC Science & Technology

2008-05-19

AFRL-RV-HA-TR-2008-1108 Vector Fluxgate Magnetometer (VMAG) Development for DSX Mark B. Moldwin Q. O O O I- UCLA Q Institute of...for Public Release; Distribution Unlimited. 13. SUPPLEMENTARY NOTES 14. ABSTRACT UCLA is building a three-axis fluxgate magnetometer for the Air... fluxgate magnetometer provides the necessary data to support both the Space Weather (SWx) specification and mapping requirements and the WPIx

Artificial Earth Satellites Designed and Fabricated by The Johns Hopkins University Applied Physics Laboratory. Revised

DTIC Science & Technology

1978-07-01

occurred. The attitude detection system included a three-axis fluxgate vector magnetometer and solar attitude detectors that produced both analog and digital ...heliogoniometer ( digital solar attitudeIsensing system) Three axis analog solar detection - Rubidium vapor magnetometer Three axis fluxgate magnetometer ...Telemetry: 35 channels modulating 150 MHz carrier on command Three axis solar attitude detector system Three axis fluxgate magnetometer system

Investigation of Magnetic Field Measurements.

DTIC Science & Technology

1983-02-28

Report) Ill. SUPPLEMENTARY NOTES IS. KEY WORDS (CoEntnue on revere side I necoseer mnd Identify by block mamber) AFGL Magnetometer Network Fluxgate ... Magnetometer Induction Coil Magnetometer Temperature Dependency of Fluxgate Automation of Testing 20. ABSTRACT (Coniniue an reverse aide If neeeeey and...data collection platforms. Support was also provided to AFGL to process the fluxgate magnetometer archive tapes in order to make the data available to

Attitude ground support system for the solar maximum mission spacecraft

NASA Technical Reports Server (NTRS)

Nair, G.

1980-01-01

The SMM attitude ground support system (AGSS) supports the acquisition of spacecraft roll attitude reference, performs the in-flight calibration of the attitude sensor complement, supports onboard control autonomy via onboard computer data base updates, and monitors onboard computer (OBC) performance. Initial roll attitude acquisition is accomplished by obtaining a coarse 3 axis attitude estimate from magnetometer and Sun sensor data and subsequently refining it by processing data from the fixed head star trackers. In-flight calibration of the attitude sensor complement is achieved by processing data from a series of slew maneuvers designed to maximize the observability and accuracy of the appropriate alignments and biases. To ensure autonomy of spacecraft operation, the AGSS selects guide stars and computes sensor occultation information for uplink to the OBC. The onboard attitude control performance is monitored on the ground through periodic attitude determination and processing of OBC data in downlink telemetry. In general, the control performance has met mission requirements. However, software and hardware problems have resulted in sporadic attitude reference losses.

Vector Fluxgate Magnetometer (VMAG) Development for DSX

DTIC Science & Technology

2010-06-03

AFRL-RV-HA-TR-2010-1056 Vector Fluxgate Magnetometer (VMAG) Development for DSX Mark B. Moldwin UCLA Institute of Geophysics... Fluxgate Magnetometer (VMAG) Development for DSX 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62601F 6. AUTHOR(S) Mark B. Moldwin 5d. PROJECT...axis fluxgate magnetometer for the AFRL-mission. The instrument is designed to measure the medium-Earth orbit geomagnetic field with precision of 0.1

Symmetry Induced Heteroclinic Cycles in Coupled Sensor Devices

DTIC Science & Technology

2012-01-01

of an array of magnetic sensors. In particular, we consider arrays made up of fluxgate magnetometers inductively coupled through electronic circuits. c...cycle can significantly enhance the sensitivity of an array of magnetic sensors. In particular, we consider arrays made up of fluxgate magnetometers ...IUTAM 5 ( 2012 ) 144 – 150 4. A Cycle in A Coupled-Core Fluxgate Magnetometer 4.1. Modeling In its most basic form, a fluxgate magnetometer

Underwater (UW) Unexploded Ordnance (UXO) Multi-Sensor Data Base (MSDB) Collection

DTIC Science & Technology

2009-07-01

11 FIGURE 6 RTG SENSOR. FOUR SENSOR TRIADS ARE SHOWN, EACH WITH A 3-AXIS FLUXGATE MAGNETOMETER ...used by RTG to measure the gradients. Each triad includes a 3-axis fluxgate magnetometer and a set of feedback coils. The outputs of three triad...each with a 3-axis fluxgate magnetometer (internal, not clearly visible) and a set of 3 feedback coils. The upper triad 3-axis magnetometer

Vector Fluxgate Magnetometer (VMAG) Development for DSX

DTIC Science & Technology

2007-07-02

AFRL-RV-HA-TR-2007-1077 Vector Fluxgate Magnetometer (VMAG) Development for DSX -- Mark B. Moldwin 0 UCLA Institute of Geophysics and Planetary...02-07-2007IScientific Report No. 2 April 2006 - April 2007 4. TITLE AND SUBTITLE S. CONTRACT NUMBER Vector Fluxgate Magnetometer (VMAG) Development...SUPPLEMENTARY NOTES 14. ABSTRACT UCLA is building a three-axis fluxgate magnetometer for the AFRL-mission. The instrument is designed to measure the medium

The Pioneer XI high field fluxgate magnetometer

NASA Technical Reports Server (NTRS)

Acuna, M. A.; Ness, N. F.

1975-01-01

The high field fluxgate magnetometer experiment flown aboard the Pioneer XI spacecraft is described. This extremely simple instrument was used to extend the spacecraft's upper-limit measurement capability by approximately an order of magnitude (from 0.14 mT to 1.00 mT) with minimum power and volume requirements. This magnetometer was designed to complement the low-field measurements provided by a helium vector magnetometer and utilizes magnetic ring core sensors with biaxial orthogonal sense coils. The instrument is a single-range, triaxial-fluxgate magnetometer capable of measuring fields of up to 1 mT along each orthogonal axis, with a maximum resolution of 1 microT.

Processing of DMSP magnetic data and its use in geomagnetic field modeling

NASA Technical Reports Server (NTRS)

Ridgway, J. R.; Sabaka, T. J.; Chinn, D.; Langel, R. A.

1989-01-01

The DMSP F-7 satellite is an operational Air Force meteorological satellite which carried a magnetometer for geophysical measurements. The magnetometer was located within the body of the spacecraft in the presence of large spacecraft fields. In addition to stray magnetic fields, the data have inherent position and time inaccuracies. Algorithms were developed to identify and remove time varying magnetic field noise from the data. Techniques developed for Magsat were then modified and used to attempt determination of the spacecraft fields, of any rotation between the magnetometer axes and the spacecraft axes, and of any scale changes within the magnetometer itself. The corrected data were then used to attempt to model the geomagnetic field. This was done in combination with data from Magsat, from the standard magnetic observatories, from aeromagnetic and other survey data, and from DE-2 spacecraft field data. Future DMSP missions can be upgraded in terms of geomagnetic measurements by upgrading the time and position information furnished with the data, placing the magnetometer at the end of the boom, upgrading the attitude determination at the magnetometer, and increasing the accuracy of the magnetometer.

Near-Earth plasma sheet boundary dynamics during substorm dipolarization

NASA Astrophysics Data System (ADS)

Nakamura, Rumi; Nagai, Tsugunobu; Birn, Joachim; Sergeev, Victor A.; Le Contel, Olivier; Varsani, Ali; Baumjohann, Wolfgang; Nakamura, Takuma; Apatenkov, Sergey; Artemyev, Anton; Ergun, Robert E.; Fuselier, Stephen A.; Gershman, Daniel J.; Giles, Barbara J.; Khotyaintsev, Yuri V.; Lindqvist, Per-Arne; Magnes, Werner; Mauk, Barry; Russell, Christopher T.; Singer, Howard J.; Stawarz, Julia; Strangeway, Robert J.; Anderson, Brian; Bromund, Ken R.; Fischer, David; Kepko, Laurence; Le, Guan; Plaschke, Ferdinand; Slavin, James A.; Cohen, Ian; Jaynes, Allison; Turner, Drew L.

2017-09-01

We report on the large-scale evolution of dipolarization in the near-Earth plasma sheet during an intense (AL -1000 nT) substorm on August 10, 2016, when multiple spacecraft at radial distances between 4 and 15 R E were present in the night-side magnetosphere. This global dipolarization consisted of multiple short-timescale (a couple of minutes) B z disturbances detected by spacecraft distributed over 9 MLT, consistent with the large-scale substorm current wedge observed by ground-based magnetometers. The four spacecraft of the Magnetospheric Multiscale were located in the southern hemisphere plasma sheet and observed fast flow disturbances associated with this dipolarization. The high-time-resolution measurements from MMS enable us to detect the rapid motion of the field structures and flow disturbances separately. A distinct pattern of the flow and field disturbance near the plasma boundaries was found. We suggest that a vortex motion created around the localized flows resulted in another field-aligned current system at the off-equatorial side of the BBF-associated R1/R2 systems, as was predicted by the MHD simulation of a localized reconnection jet. The observations by GOES and Geotail, which were located in the opposite hemisphere and local time, support this view. We demonstrate that the processes of both Earthward flow braking and of accumulated magnetic flux evolving tailward also control the dynamics in the boundary region of the near-Earth plasma sheet.[Figure not available: see fulltext.

International solar polar mission: The vector helium magnetometer

NASA Technical Reports Server (NTRS)

1982-01-01

The functional requirements for the vector helium magnetometer (VHM) on the Solar Polar spacecraft are presented. The VHM is one of the two magnetometers on board that will measure the vector magnetic field along the Earth to Jupiter transfer trajectory, as well as in the vicinity of Jupiter and along the solar polar orbit following the Jupiter encounter. The interconnection between these two magnetometers and their shared data processing unit is illustrated.

An evaluation of the accuracy of geomagnetic data obtained from an unattended, automated, quasi-absolute station

USGS Publications Warehouse

Herzog, D.C.

1990-01-01

A comparison is made of geomagnetic calibration data obtained from a high-sensitivity proton magnetometer enclosed within an orthogonal bias coil system, with data obtained from standard procedures at a mid-latitude U.S. Geological Survey magnetic observatory using a quartz horizontal magnetometer, a Ruska magnetometer, and a total field magnetometer. The orthogonal coil arrangement is used with the proton magnetometer to provide Deflected-Inclination-Deflected-Declination (DIDD) data from which quasi-absolute values of declination, horizontal intensity, and vertical intensity can be derived. Vector magnetometers provide the ordinate values to yield baseline calibrations for both the DIDD and standard observatory processes. Results obtained from a prototype system over a period of several months indicate that the DIDD unit can furnish adequate absolute field values for maintaining observatory calibration data, thus providing baseline control for unattended, remote stations. ?? 1990.

High Sensitivity Optically Pumped Quantum Magnetometer

PubMed Central

Tiporlini, Valentina; Alameh, Kamal

2013-01-01

Quantum magnetometers based on optical pumping can achieve sensitivity as high as what SQUID-based devices can attain. In this paper, we discuss the principle of operation and the optimal design of an optically pumped quantum magnetometer. The ultimate intrinsic sensitivity is calculated showing that optimal performance of the magnetometer is attained with an optical pump power of 20 μW and an operation temperature of 48°C. Results show that the ultimate intrinsic sensitivity of the quantum magnetometer that can be achieved is 327 fT/Hz1/2 over a bandwidth of 26 Hz and that this sensitivity drops to 130 pT/Hz1/2 in the presence of environmental noise. The quantum magnetometer is shown to be capable of detecting a sinusoidal magnetic field of amplitude as low as 15 pT oscillating at 25 Hz. PMID:23766716

Gravity-Off-loading System for Large-Displacement Ground Testing of Spacecraft Mechanisms

NASA Technical Reports Server (NTRS)

Han, Olyvia; Kienholz, David; Janzen, Paul; Kidney, Scott

2010-01-01

Gravity-off-loading of deployable spacecraft mechanisms during ground testing is a long-standing problem. Deployable structures which are usually too weak to support their own weight under gravity require a means of gravity-off-loading as they unfurl. Conventional solutions to this problem have been helium-filled balloons or mechanical pulley/counterweight systems. These approaches, however, suffer from the deleterious effects of added inertia or friction forces. The changing form factor of the deployable structure itself and the need to track the trajectory of the center of gravity also pose a challenge to these conventional technologies. This paper presents a novel testing apparatus for high-fidelity zero-gravity simulation for special application to deployable space structures such as solar arrays, magnetometer booms, and robotic arms in class 100,000 clean room environments

Soil anomaly mapping using a caesium magnetometer: Limits in the low magnetic amplitude case

NASA Astrophysics Data System (ADS)

Mathé, Vivien; Lévêque, François; Mathé, Pierre-Etienne; Chevallier, Claude; Pons, Yves

2006-03-01

Caesium magnetometers are new tools for soil property mapping with a decimetric resolution [Mathé, V., Lévêque, F., 2003. High resolution magnetic survey for soil monitoring: detection of drainage and soil tillage effects. Earth and Planetary Science Letters 212 (1-2), 241-251]. However, when the magnetic anomalies are only a few nanoteslas (nT), the geologic and pedogenic signal must first be isolated from magnetic disturbances for this method to be useful. This paper investigates the instrumental artifacts and environmental disturbances to adapt the survey protocol to slightly magnetic soils. Among the possible instrumental sources of disturbances listed and quantified, the most significant are: 1) The battery effect upon sensors 2 m away (classic protocol, about ± 0.15 nT) while increasing this distance up to 10 m cancelled it; 2) The noise level of magnetometers and sensors, which, according to tests on two magnetometers and three sensors, rarely and randomly exceeds 0.1 nT, but seems to increase with the electronic component age. Among the environmental disturbances, temporal variations such as diurnal variation or fluctuations linked to the moving of metallic masses play a major role, although the pseudogradient or base-station methods have commonly cancelled them. The efficiency of the latter is strongly dependent on the source nature. However, the ground currents and electromagnetic fields propagating in soils cause more problems. As a first step to better understand such disturbance sources, uncommon magnetic signal variations supposedly due to electromagnetic wave conversions and likely linked to the railway traffic are presented. Based on previous results, an adapted protocol using one magnetometer and two caesium sensors (0.3 and 1.6 m above the surface) is proposed to increase the signal / noise ratio. At first, to maintain an accurate horizontal and vertical location of the sensors, the latter are affixed to a wooden handcart running on plastic rails. Rails adapt to micro-topography, thereby decreasing strongly the soil-sensors distance variations. Anomalies due to topography rarely exceed 0.1 nT. Finally, a method to remove diurnal variations from high-resolution magnetic maps is proposed. Parallel profiles performed successively are adjusted by a cross-profile. Assuming that the temporal variations during each profile are negligible (less than 0.05 nT), this technique, contrary to the pseudogradient, preserves both the decimetric and the metric anomalies (gain of more than 1 nT).

Alignment of a vector magnetometer to an optical prism

NASA Astrophysics Data System (ADS)

Dietrich, M. R.; Bailey, K. G.; O'Connor, T. P.

2017-05-01

A method for alignment of a vector magnetometer to a rigidly attached prism is presented. This enables optical comparison of the magnetometer axes to physical surfaces in the apparatus, and thus an absolute determination of the magnetic field direction in space. This is in contrast with more common techniques, which focus on precise determination of the relative angles between magnetometer axes, and so are more suited to measuring differences in the direction of magnetic fields. Here we demonstrate precision better than 500 μrad on a fluxgate magnetometer, which also gives the coil orthogonality errors to a similar precision. The relative sensitivity of the three axes is also determined, with a precision of about 5 ×10 -4 .

Correcting GOES-R Magnetometer Data for Stray Fields

NASA Technical Reports Server (NTRS)

Carter, Delano R.; Freesland, Douglas C.; Tadikonda, Sivakumara K.; Kronenwetter, Jeffrey; Todirita, Monica; Dahya, Melissa; Chu, Donald

2016-01-01

Time-varying spacecraft magnetic fields or stray fields are a problem for magnetometer systems. While constant fields can be removed with zero offset calibration, stray fields are difficult to distinguish from ambient field variations. Putting two magnetometers on a long boom and solving for both the ambient and stray fields can be a good idea, but this gradiometer solution is even more susceptible to noise than a single magnetometer. Unless the stray fields are larger than the magnetometer noise, simply averaging the two measurements is a more accurate approach. If averaging is used, it may be worthwhile to explicitly estimate and remove stray fields. Models and estimation algorithms are provided for solar array, arcjet and reaction wheel fields.

Sticky Bomb Detection With Other Implications For Vehicle Security

DTIC Science & Technology

2010-04-15

performance of two commercial magnetometers . The first was a handheld Walker Scientific Triaxial FluxGate Magnetometer with a 1 nanoTesla (nT) resolution...along each of 3 axes. The other ! !!!!!!!!!!!!!!!!!!!!!!!!!"#$%&’(!#)!*+,-./’(!01/$%.2,!34567!89:39!4;ɝɞ! ! 38! magnetometer was a PNI V2XE 2-axis...Argonne, IL is approximately 45,000 nT at the surface.) Readings from the Walker magnetometer were recorded manually from the liquid crystal

Achieving High Sensitivity in Cavity Optomechanical Magnetometry

DTIC Science & Technology

2014-03-08

magnetometers, but with microwatts of power consumption, and without the need for cryogenics. This project was to implement magnetometers at both micro- and...state-of-the-art in SQUID magnetometers, but with microwatts of power consumption, and without the need for cryogenics. This project was to implement...microwatts  of   power   and  at  room  temperature.  This  first  year  of  the  project  fabricated  new  magnetometer

Magnetosphere-Ionosphere Coupling During a Geomagnetic Substorm on March 1, 2017

NASA Astrophysics Data System (ADS)

Coster, A. J.; Hampton, D. L.; Sazykin, S. Y.; Wolf, R.; Huba, J.; Varney, R. H.; Reimer, A.; Lynch, K. A.; Samara, M.; Michell, R.

2017-12-01

On March 1, 2017, at approximately 10 UT, magnetometers at Ft Yukon and Poker Flat in Alaska measured the classic signature of an auroral substorm: a rapid decrease in the northward component of the magnetic field. Nearby, a camera at Venetie Alaska captured intensive visual brightening of multiple auroral arcs at approximately the same time. Our data and model analysis focuses on this time period. We are taking advantage of the extensive instrumentation that was in place in Northern Alaska on this date due to the ISINGLASS rocket campaign. Although no rockets were flown on March 1, 2017, this substorm was monitored at Poker by the three-filter all-sky survey and at Venetie by three all-sky cameras running simultaneously with each filtered for a different wavelength. Our analysis includes co-incidental high precision GNSS receiver data providing total electron content (TEC) measurements during the overhead auroral arcs. The receiver at Venetie also monitored L-band scintillation. In addition, the Poker Flat Incoherent Scatter radar captured the rapid ionization enhancement in the 100-200 km region across multiple beams looking to the north of Poker. The timing of these events between the multiple sites is closely monitored, and inferences of the propagation of this event are described. The available SuperDARN data from this time period indicates this substorm happened at about the same time within the Harang discontinuity. This event presented an unprecedented opportunity to observe occurrence and development of a substorm with a combination of ground-based remote sensing instruments. To support our interpretation of the data, we present first simulations of the magnetosphere-ionosphere coupled system during a substorm with the self-consistently coupled SAMI/RCM code.

Study of the Equatorial and Low-Latitude Electrodynamic and Ionospheric Disturbances During the 22-23 June 2015 Geomagnetic Storm Using Ground-Based and Spaceborne Techniques

NASA Astrophysics Data System (ADS)

Astafyeva, E.; Zakharenkova, I.; Hozumi, K.; Alken, P.; Coïsson, P.; Hairston, M. R.; Coley, W. R.

2018-03-01

We use a set of ground-based instruments (Global Positioning System receivers, ionosondes, magnetometers) along with data of multiple satellite missions (Swarm, C/NOFS, DMSP, GUVI) to analyze the equatorial and low-latitude electrodynamic and ionospheric disturbances caused by the geomagnetic storm of 22-23 June 2015, which is the second largest storm in the current solar cycle. Our results show that at the beginning of the storm, the equatorial electrojet (EEJ) and the equatorial zonal electric fields were largely impacted by the prompt penetration electric fields (PPEF). The PPEF were first directed eastward and caused significant ionospheric uplift and positive ionospheric storm on the dayside, and downward drift on the nightside. Furthermore, about 45 min after the storm commencement, the interplanetary magnetic field (IMF) Bz component turned northward, leading to the EEJ changing sign to westward, and to overall decrease of the vertical total electron content (VTEC) and electron density on the dayside. At the end of the main phase of the storm, and with the second long-term IMF Bz southward turn, we observed several oscillations of the EEJ, which led us to conclude that at this stage of the storm, the disturbance dynamo effect was already in effect, competing with the PPEF and reducing it. Our analysis showed no significant upward or downward plasma motion during this period of time; however, the electron density and the VTEC drastically increased on the dayside (over the Asian region). We show that this second positive storm was largely influenced by the disturbed thermospheric conditions.

Calibration of Magnetometers with GNSS Receivers and Magnetometer-Aided GNSS Ambiguity Fixing

PubMed Central

Henkel, Patrick

2017-01-01

Magnetometers provide compass information, and are widely used for navigation, orientation and alignment of objects. As magnetometers are affected by sensor biases and eventually by systematic distortions of the Earth magnetic field, a calibration is needed. In this paper, a method for calibration of magnetometers with three Global Navigation Satellite System (GNSS) receivers is presented. We perform a least-squares estimation of the magnetic flux and sensor biases using GNSS-based attitude information. The attitude is obtained from the relative positions between the GNSS receivers in the North-East-Down coordinate frame and prior knowledge of these relative positions in the platform’s coordinate frame. The relative positions and integer ambiguities of the periodic carrier phase measurements are determined with an integer least-squares estimation using an integer decorrelation and sequential tree search. Prior knowledge on the relative positions is used to increase the success rate of ambiguity fixing. We have validated the proposed method with low-cost magnetometers and GNSS receivers on a vehicle in a test drive. The calibration enabled a consistent heading determination with an accuracy of five degrees. This precise magnetometer-based attitude information allows an instantaneous GNSS integer ambiguity fixing. PMID:28594369

An Attitude Filtering and Magnetometer Calibration Approach for Nanosatellites

NASA Astrophysics Data System (ADS)

Söken, Halil Ersin

2018-04-01

We propose an attitude filtering and magnetometer calibration approach for nanosatellites. Measurements from magnetometers, Sun sensor and gyros are used in the filtering algorithm to estimate the attitude of the satellite together with the bias terms for the gyros and magnetometers. In the traditional approach for the attitude filtering, the attitude sensor measurements are used in the filter with a nonlinear vector measurement model. In the proposed algorithm, the TRIAD algorithm is used in conjunction with the unscented Kalman filter (UKF) to form the nontraditional attitude filter. First the vector measurements from the magnetometer and Sun sensor are processed with the TRIAD algorithm to obtain a coarse attitude estimate for the spacecraft. In the second phase the estimated coarse attitude is used as quaternion measurements for the UKF. The UKF estimates the fine attitude, and the gyro and magnetometer biases. We evaluate the algorithm for a hypothetical nanosatellite by numerical simulations. The results show that the attitude of the satellite can be estimated with an accuracy better than 0.5{°} and the computational load decreases more than 25% compared to a traditional UKF algorithm. We discuss the algorithm's performance in case of a time-variance in the magnetometer errors.

Low-Tc direct current superconducting quantum interference device magnetometer-based 36-channel magnetocardiography system in a magnetically shielded room

NASA Astrophysics Data System (ADS)

Qiu, Yang; Li, Hua; Zhang, Shu-Lin; Wang, Yong-Liang; Kong, Xiang-Yan; Zhang, Chao-Xiang; Zhang, Yong-Sheng; Xu, Xiao-Feng; Yang, Kang; Xie, Xiao-Ming

2015-07-01

We constructed a 36-channel magnetocardiography (MCG) system based on low-Tc direct current (DC) superconducting quantum interference device (SQUID) magnetometers operated inside a magnetically shielded room (MSR). Weakly damped SQUID magnetometers with large Steward-McCumber parameter βc (βc ≈ 5), which could directly connect to the operational amplifier without any additional feedback circuit, were used to simplify the readout electronics. With a flux-to-voltage transfer coefficient ∂ V/∂ Φ larger than 420 μV/Φ 0, the SQUID magnetometers had a white noise level of about 5.5 fT·Hz-1/2 when operated in MSR. 36 sensing magnetometers and 15 reference magnetometers were employed to realize software gradiometer configurations. The coverage area of the 36 sensing magnetometers is 210×210 mm2. MCG measurements with a high signal-to-noise ratio of 40 dB were done successfully using the developed system. Project supported by “One Hundred Persons Project” of the Chinese Academy of Sciences and the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (Grant No. XDB04020200).

Calibration of Magnetometers with GNSS Receivers and Magnetometer-Aided GNSS Ambiguity Fixing.

PubMed

Henkel, Patrick

2017-06-08

Magnetometers provide compass information, and are widely used for navigation, orientation and alignment of objects. As magnetometers are affected by sensor biases and eventually by systematic distortions of the Earth magnetic field, a calibration is needed. In this paper, a method for calibration of magnetometers with three Global Navigation Satellite System (GNSS) receivers is presented. We perform a least-squares estimation of the magnetic flux and sensor biases using GNSS-based attitude information. The attitude is obtained from the relative positions between the GNSS receivers in the North-East-Down coordinate frame and prior knowledge of these relative positions in the platform's coordinate frame. The relative positions and integer ambiguities of the periodic carrier phase measurements are determined with an integer least-squares estimation using an integer decorrelation and sequential tree search. Prior knowledge on the relative positions is used to increase the success rate of ambiguity fixing. We have validated the proposed method with low-cost magnetometers and GNSS receivers on a vehicle in a test drive. The calibration enabled a consistent heading determination with an accuracy of five degrees. This precise magnetometer-based attitude information allows an instantaneous GNSS integer ambiguity fixing.

Balloon-Borne, High Altitude Gravimetry: The Flight of DUCKY Ia (11 October 1983)

DTIC Science & Technology

1985-12-31

three rate gyros, three-axis magnetometer and two tiltmeters ) combined with ground tracking (X, Y and Z position and velocity) will allow fqX_.,ep ar a...2.3 Sensors 9 2.3.1 Vibrating String Accelerometer (VSA) 9 2.3.1.1 Mechanical Liyout of’ System 10 2.3.i.2 VSA System Description i0 2.3.1.3 Method for...Block Diagram 11 2.2 A Sketch of the VSA Sensor 12 3.1 A Photograph of the Payload, Named DUCKY Ia, Just After Transport to the Launch Site 22 3.2 A

Pointing system for the balloon-borne astronomical payloads

NASA Astrophysics Data System (ADS)

Nirmal, Kaipacheri; Sreejith, Aickara Gopinathan; Mathew, Joice; Sarpotdar, Mayuresh; Ambily, Suresh; Prakash, Ajin; Safonova, Margarita; Murthy, Jayant

2016-10-01

We describe the development and implementation of a light-weight, fully autonomous 2-axis pointing and stabilization system designed for balloon-borne astronomical payloads. The system is developed using off-the-shelf components such as Arduino Uno controller, HMC 5883L magnetometer, MPU-9150 inertial measurement unit, and iWave GPS receiver unit. It is a compact and rugged system which can also be used to take images/video in a moving vehicle or in real photography. The system performance is evaluated from the ground, as well as in conditions simulated to imitate the actual flight by using a tethered launch.

Relations between morning sector Pi 1 pulsation activity and particle and field characteristics observed by the DE 2 satellite

NASA Technical Reports Server (NTRS)

Engebretson, M. J.; Cahill, L. J., Jr.; Winningham, J. D.; Rosenberg, T. J.; Arnoldy, R. L.; Maynard, N. C.; Sugiura, M.

1986-01-01

Ground-based magnetometer, photometer, and riometer data are combined with low-altitude particle and electric and magnetic field data from the DE-2 spacecraft to provide a more complete characterization of the magnetospheric and tropospheric environment in which morning sector asymmetric Pi 1 pulsations are observed. The results of the study are in agreement with recent conclusions that morning sector asymmetric Pi 1 pulsations are physically related to pulsating aurorae. Precipitation of energetic electrons (E greater than 35 keV) coincides in every instance with the occurrence of these pulsations.

National Geomagnetism Program: Current Status & Five-Year Plan, 2006-2010

USGS Publications Warehouse

Love, Jeffrey J.

2006-01-01

Executive Summary: The U.S. Geological Survey's Geomagnetism Program serves the scientific community and the broader public by collecting and distributing magnetometer data from an array of ground-based observatories and by conducting scientific analysis on those data. Preliminary, variational time-series can be collected and distributed in near-real time, while fully calibrated, absolute time-series are distributed after processing. The data are used by the civilian and military parts of the Federal Government, by private industry, and by academia, for a wide variety of purposes of both immediately practical importance and long-term scientific interest, including space-weather diagnosis and related hazard mitigation, mapping of the magnetic field and measurement of its activity, and research on the nature of the Earth's interior and the near-Earth space environment. This document reviews the current status of the Program, in terms of its situation within the Government and within the scientific community; summarizes the Program's operations, its staffing situation, and its facilities; describes the diversity of uses of Program magnetometer data; and presents a plan for the next 5 years for enhancing the Program's data-based services, developing products, and conducting scientific research.

NEWTON - NEW portable multi-sensor scienTific instrument for non-invasive ON-site characterization of rock from planetary surface and sub-surfaces

NASA Astrophysics Data System (ADS)

Díaz-Michelena, M.; de Frutos, J.; Ordóñez, A. A.; Rivero, M. A.; Mesa, J. L.; González, L.; Lavín, C.; Aroca, C.; Sanz, M.; Maicas, M.; Prieto, J. L.; Cobos, P.; Pérez, M.; Kilian, R.; Baeza, O.; Langlais, B.; Thébault, E.; Grösser, J.; Pappusch, M.

2017-09-01

In space instrumentation, there is currently no instrument dedicated to susceptibly or complete magnetization measurements of rocks. Magnetic field instrument suites are generally vector (or scalar) magnetometers, which locally measure the magnetic field. When mounted on board rovers, the electromagnetic perturbations associated with motors and other elements make it difficult to reap the benefits from the inclusion of such instruments. However, magnetic characterization is essential to understand key aspects of the present and past history of planetary objects. The work presented here overcomes the limitations currently existing in space instrumentation by developing a new portable and compact multi-sensor instrument for ground breaking high-resolution magnetic characterization of planetary surfaces and sub-surfaces. This new technology introduces for the first time magnetic susceptometry (real and imaginary parts) as a complement to existing compact vector magnetometers for planetary exploration. This work aims to solve the limitations currently existing in space instrumentation by means of providing a new portable and compact multi-sensor instrument for use in space, science and planetary exploration to solve some of the open questions on the crustal and more generally planetary evolution within the Solar System.

Progress of the MAGDAS Project During 2013

NASA Astrophysics Data System (ADS)

Maeda, G.; Yoshikawa, A.; Abe, S.

2013-12-01

The magnetometer array of the MAGDAS Project is perhaps the largest magnetometer array in the world -- with 71 real time magnetometers deployed around the world. In this presentation we explain the latest status of this array and the latest data release policy. In addition, we describe various MAGDAS activities of this year, such as: (1) the ISWI and MAGDAS School in Africa, (2) the ISWI/MAGDAS presentation by the MAGDAS PI at Graz, Austria, and (3) the maintenance work done in the field for magnetometers.

Aeromagnetic Compensation for UAVs

NASA Astrophysics Data System (ADS)

Naprstek, T.; Lee, M. D.

2017-12-01

Aeromagnetic data is one of the most widely collected types of data in exploration geophysics. With the continuing prevalence of unmanned air vehicles (UAVs) in everyday life there is a strong push for aeromagnetic data collection using UAVs. However, apart from the many political and legal barriers to overcome in the development of UAVs as aeromagnetic data collection platforms, there are also significant scientific hurdles, primary of which is magnetic compensation. This is a well-established process in manned aircraft achieved through a combination of platform magnetic de-noising and compensation routines. However, not all of this protocol can be directly applied to UAVs due to fundamental differences in the platforms, most notably the decrease in scale causing magnetometers to be significantly closer to the avionics. As such, the methodology must be suitably adjusted. The National Research Council of Canada has collaborated with Aeromagnetic Solutions Incorporated to develop a standardized approach to de-noising and compensating UAVs, which is accomplished through a series of static and dynamic experiments. On the ground, small static tests are conducted on individual components to determine their magnetization. If they are highly magnetic, they are removed, demagnetized, or characterized such that they can be accounted for in the compensation. Dynamic tests can include measuring specific components as they are powered on and off to assess their potential effect on airborne data. The UAV is then flown, and a modified compensation routine is applied. These modifications include utilizing onboard autopilot current sensors as additional terms in the compensation algorithm. This process has been applied with success to fixed-wing and rotary-wing platforms, with both a standard manned-aircraft magnetometer, as well as a new atomic magnetometer, much smaller in scale.

Recent Activities on the Embrace Space Weather Regional Warning Center: the New Space Weather Data Center

NASA Astrophysics Data System (ADS)

Denardini, Clezio Marcos; Dal Lago, Alisson; Mendes, Odim; Batista, Inez S.; SantAnna, Nilson; Gatto, Rubens; Takahashi, Hisao; Costa, D. Joaquim; Banik Padua, Marcelo; Campos Velho, Haroldo

2016-07-01

On August 2007 the National Institute for Space Research started a task force to develop and operate a space weather program, which is known by the acronyms Embrace that stands for the Portuguese statement "Estudo e Monitoramento BRAasileiro de Clima Espacial" Program (Brazilian Space Weather Study and Monitoring program). The mission of the Embrace/INPE program is to monitor the Solar-Terrestrial environment, the magnetosphere, the upper atmosphere and the ground induced currents to prevent effects on technological and economic activities. The Embrace/INPE system monitors the physical parameters of the Sun-Earth environment, such as Active Regions (AR) in the Sun and solar radiation by using radio telescope, Coronal Mass Ejection (CME) information by satellite and ground-based cosmic ray monitoring, geomagnetic activity by the magnetometer network, and ionospheric disturbance by ionospheric sounders and using data collected by four GPS receiver network, geomagnetic activity by a magnetometer network, and provides a forecasting for Total Electronic Content (TEC) - 24 hours ahead - using a version of the SUPIM model which assimilates the two latter data using nudging approach. Most of these physical parameters are daily published on the Brazilian space weather program web portal, related to the entire network sensors available. Regarding outreach, it has being published a daily bulletin in Portuguese and English with the status of the space weather environment on the Sun, the Interplanetary Medium and close to the Earth. Since December 2011, all these activities are carried out at the Embrace Headquarter, a building located at the INPE's main campus. Recently, a comprehensive data bank and an interface layer are under commissioning to allow an easy and direct access to all the space weather data collected by Embrace through the Embrace web Portal. The information being released encompasses data from: (a) the Embrace Digisonde Network (Embrace DigiNet) that monitors the ionospheric profiles in two equatorial sites and in two low latitude sites; (b) several solar radio telescopes to monitor solar activity (under development); (c) the matrix of the GNSS TEC map over South America; (d) the Embrace Airglow All-sky Imagers Network (Embrace GlowNet); and (d) the Embrace Magnetometer Network (Embrace Magnet), all of them in South America. Also, the system allows subscription to space weather alerts and reports. Contacting Author: C. M. Denardini (clezio.denardin@inpe.br)

Multi-event study of high-latitude thermospheric wind variations at substorm onset with a Fabry-Perot interferometer at Tromsoe, Norway

NASA Astrophysics Data System (ADS)

Xu, H.; Shiokawa, K.; Oyama, S. I.; Otsuka, Y.

2017-12-01

We studied the high-latitude thermospheric wind variations near the onset time of isolated substorms. Substorm-related energy input from the magnetosphere to the polar ionosphere modifies the high-latitude ionosphere and thermosphere. For the first time, this study showed the characteristics of high-latitude thermospheric wind variations at the substorm onset. We also investigated the possibility of these wind variations as a potential trigger of substorm onset by modifying the ionospheric current system (Kan, 1993). A Fabry-Perot interferometer (FPI) at Tromsoe, Norway provided wind measurements estimated from Doppler shift of both red-line (630.0 nm for the F region) and green-line (557.7 nm for the E region) emissions of aurora and airglow. We used seven-year data sets obtained from 2009 to 2015 with a time resolution of 13 min. We first identified the onset times of local isolated substorms using ground-based magnetometer data obtained at the Tromsoe and Bear Island stations, which belongs to the IMAGE magnetometer chain. We obtained 4 red-line events and 5 green-line events taken place at different local times. For all these events, the peak locations of westward ionospheric currents identified by the ground-based magnetometer chain were located at the poleward side of Tromsoe. Then, we calculated two weighted averages of wind velocities for 30 min around the onset time and 30 min after the onset time of substorms. We evaluated differences between these two weighted averages to estimate the strength of wind changes. The observed wind changes at these substorm onsets were less than 49 m/s (26 m/s) for red-line (green-line) events, which are much smaller than the typical plasma convection speed. This indicates that the plasma motion caused by substorm-induced thermospheric winds through ion-neutral collisions is a minor effect as the driver of high-latitude plasma convection, as well as the triggering of substorm onset. We discuss possible causes of these observed wind changes at the onset of substorms based on the mechanisms of thermospheric diurnal tides, arc-induced electric field and Joule heating caused by the auroral activities that were identified by the cross sections of all-sky images, as well as the IMF-associated plasma convection model.

Alignment of a vector magnetometer to an optical prism.

PubMed

Dietrich, M R; Bailey, K G; O'Connor, T P

2017-05-01

A method for alignment of a vector magnetometer to a rigidly attached prism is presented. This enables optical comparison of the magnetometer axes to physical surfaces in the apparatus, and thus an absolute determination of the magnetic field direction in space. This is in contrast with more common techniques, which focus on precise determination of the relative angles between magnetometer axes, and so are more suited to measuring differences in the direction of magnetic fields. Here we demonstrate precision better than 500 μrad on a fluxgate magnetometer, which also gives the coil orthogonality errors to a similar precision. The relative sensitivity of the three axes is also determined, with a precision of about 5 × 10 -4 .

Sensitivity optimization of Bell-Bloom magnetometers by manipulation of atomic spin synchronization

NASA Astrophysics Data System (ADS)

Ranjbaran, M.; Tehranchi, M. M.; Hamidi, S. M.; Khalkhali, S. M. H.

2018-05-01

Many efforts have been devoted to the developments of atomic magnetometers for achieving the high sensitivity required in biomagnetic applications. To reach the high sensitivity, many types of atomic magnetometers have been introduced for optimization of the creation and relaxation rates of atomic spin polarization. In this paper, regards to sensitivity optimization techniques in the Mx configuration, we have proposed a novelty approach for synchronization of the spin precession in the Bell-Bloom magnetometers. We have utilized the phenomenological Bloch equations to simulate the spin dynamics when modulation of pumping light and radio frequency magnetic field were both used for atomic spin synchronization. Our results showed that the synchronization process, improved the magnetometer sensitivity respect to the classical configurations.

Optimization of multimagnetometer systems on a spacecraft

NASA Technical Reports Server (NTRS)

Neubauer, F. M.

1975-01-01

The problem of optimizing the position of magnetometers along a boom of given length to yield a minimized total error is investigated. The discussion is limited to at most four magnetometers, which seems to be a practical limit due to weight, power, and financial considerations. The outlined error analysis is applied to some illustrative cases. The optimal magnetometer locations, for which the total error is minimum, are computed for given boom length, instrument errors, and very conservative magnetic field models characteristic for spacecraft with only a restricted or ineffective magnetic cleanliness program. It is shown that the error contribution by the magnetometer inaccuracy is increased as the number of magnetometers is increased, whereas the spacecraft field uncertainty is diminished by an appreciably larger amount.

Nonlinear temperature compensation of fluxgate magnetometers with a least-squares support vector machine

NASA Astrophysics Data System (ADS)

Pang, Hongfeng; Chen, Dixiang; Pan, Mengchun; Luo, Shitu; Zhang, Qi; Luo, Feilu

2012-02-01

Fluxgate magnetometers are widely used for magnetic field measurement. However, their accuracy is influenced by temperature. In this paper, a new method was proposed to compensate the temperature drift of fluxgate magnetometers, in which a least-squares support vector machine (LSSVM) is utilized. The compensation performance was analyzed by simulation, which shows that the LSSVM has better performance and less training time than backpropagation and radical basis function neural networks. The temperature characteristics of a DM fluxgate magnetometer were measured with a temperature experiment box. Forty-five measured data under different magnetic fields and temperatures were obtained and divided into 36 training data and nine test data. The training data were used to obtain the parameters of the LSSVM model, and the compensation performance of the LSSVM model was verified by the test data. Experimental results show that the temperature drift of magnetometer is reduced from 109.3 to 3.3 nT after compensation, which suggests that this compensation method is effective for the accuracy improvement of fluxgate magnetometers.

Analytical balance-based Faraday magnetometer

NASA Astrophysics Data System (ADS)

Riminucci, Alberto; Uhlarz, Marc; De Santis, Roberto; Herrmannsdörfer, Thomas

2017-03-01

We introduce a Faraday magnetometer based on an analytical balance in which we were able to apply magnetic fields up to 0.14 T. We calibrated it with a 1 mm Ni sphere previously characterized in a superconducting quantum interference device (SQUID) magnetometer. The proposed magnetometer reached a theoretical sensitivity of 3 × 10-8 A m2. We demonstrated its operation on magnetic composite scaffolds made of poly(ɛ-caprolactone)/iron-doped hydroxyapatite. To confirm the validity of the method, we measured the same scaffold properties in a SQUID magnetometer. The agreement between the two measurements was within 5% at 0.127 T and 12% at 24 mT. With the addition, for a small cost, of a permanent magnet and computer controlled linear translators, we were thus able to assemble a Faraday magnetometer based on an analytical balance, which is a virtually ubiquitous instrument. This will make simple but effective magnetometry easily accessible to most laboratories, in particular, to life sciences ones, which are increasingly interested in magnetic materials.

Measurement and subtraction of Schumann resonances at gravitational-wave interferometers

NASA Astrophysics Data System (ADS)

Coughlin, Michael W.; Cirone, Alessio; Meyers, Patrick; Atsuta, Sho; Boschi, Valerio; Chincarini, Andrea; Christensen, Nelson L.; De Rosa, Rosario; Effler, Anamaria; Fiori, Irene; Gołkowski, Mark; Guidry, Melissa; Harms, Jan; Hayama, Kazuhiro; Kataoka, Yuu; Kubisz, Jerzy; Kulak, Andrzej; Laxen, Michael; Matas, Andrew; Mlynarczyk, Janusz; Ogawa, Tsutomu; Paoletti, Federico; Salvador, Jacobo; Schofield, Robert; Somiya, Kentaro; Thrane, Eric

2018-05-01

Correlated magnetic noise from Schumann resonances threatens to contaminate the observation of a stochastic gravitational-wave background in interferometric detectors. In previous work, we reported on the first effort to eliminate global correlated noise from the Schumann resonances using Wiener filtering, demonstrating as much as a factor of two reduction in the coherence between magnetometers on different continents. In this work, we present results from dedicated magnetometer measurements at the Virgo and KAGRA sites, which are the first results for subtraction using data from gravitational-wave detector sites. We compare these measurements to a growing network of permanent magnetometer stations, including at the LIGO sites. We show the effect of mutual magnetometer attraction, arguing that magnetometers should be placed at least one meter from one another. In addition, for the first time, we show how dedicated measurements by magnetometers near to the interferometers can reduce coherence to a level consistent with uncorrelated noise, making a potential detection of a stochastic gravitational-wave background possible.

Infrastructure-Less Indoor Localization Using the Microphone, Magnetometer and Light Sensor of a Smartphone

PubMed Central

Galván-Tejada, Carlos E.; García-Vázquez, Juan Pablo; Galván-Tejada, Jorge I.; Delgado-Contreras, J. Rubén; Brena, Ramon F.

2015-01-01

In this paper, we present the development of an infrastructure-less indoor location system (ILS), which relies on the use of a microphone, a magnetometer and a light sensor of a smartphone, all three of which are essentially passive sensors, relying on signals available practically in any building in the world, no matter how developed the region is. In our work, we merge the information from those sensors to estimate the user’s location in an indoor environment. A multivariate model is applied to find the user’s location, and we evaluate the quality of the resulting model in terms of sensitivity and specificity. Our experiments were carried out in an office environment during summer and winter, to take into account changes in light patterns, as well as changes in the Earth’s magnetic field irregularities. The experimental results clearly show the benefits of using the information fusion of multiple sensors when contrasted with the use of a single source of information. PMID:26295237

Infrastructure-Less Indoor Localization Using the Microphone, Magnetometer and Light Sensor of a Smartphone.

PubMed

Galván-Tejada, Carlos E; García-Vázquez, Juan Pablo; Galván-Tejada, Jorge I; Delgado-Contreras, J Rubén; Brena, Ramon F

2015-08-18

In this paper, we present the development of an infrastructure-less indoor location system (ILS), which relies on the use of a microphone, a magnetometer and a light sensor of a smartphone, all three of which are essentially passive sensors, relying on signals available practically in any building in the world, no matter how developed the region is. In our work, we merge the information from those sensors to estimate the user's location in an indoor environment. A multivariate model is applied to find the user's location, and we evaluate the quality of the resulting model in terms of sensitivity and specificity. Our experiments were carried out in an office environment during summer and winter, to take into account changes in light patterns, as well as changes in the Earth's magnetic field irregularities. The experimental results clearly show the benefits of using the information fusion of multiple sensors when contrasted with the use of a single source of information.

A Guide for Collecting Seismic, Acoustic, and Magnetic Data for Multiple Uses

DTIC Science & Technology

1975-01-01

time, simul- (- taneously for the analog technique or sequentially for the digital tech- nique. Both methods require that precision timing networks be...with a precise voltage proportional to the sensitivity of the magnetometer . Whenever any electronic equip- ment affecting cal.bration has to be replaced...described as precisely as possible, including (but not limited to) the following: a. Name of source b. Continuous or transient c. Distance from geophone

Case Studies of Extreme Space Weather Effects on the New York State (NYS) Electric Power System

NASA Astrophysics Data System (ADS)

Chantale Damas, M.; Mohamed, Ahmed; Ngwira, Chigomyezo

2017-04-01

New York State (NYS) is home to one of the largest urban cities in the world, New York City (NYC). Understanding and mitigating the effects of extreme space weather events are important to reduce the vulnerabilities of the NYS present bulk power system, which includes NYC. Extreme space weather events perturb Earth's magnetic field and generate geo-electric fields that result in the flow of Geomagnetically Induced Currents (GICs) through transmission lines, followed by transformers and ground. GICs find paths to ground through transformer grounding wires causing half-cycle saturation to their magnetic cores. This causes transformers to overheat, inject harmonics to the grid and draw more reactive power than normal. Overheating, if sustained for a long duration, may lead to transformer failure or lifetime reduction. Presented work uses results from simulations performed by the Global SWMF-generated ground geomagnetic field perturbations. Results from computed values of simulated induced geo-electric fields at specific ground-based active INTERMAGNET magnetometer sites, combined with NYS electricity transmission network real data are used to examine the vulnerabilities of the NYS power grid. As an urban city with a large population, NYC is especially vulnerable and the results from this research can be used to model power systems for other urban cities.

GUMICS-4 Year Run: Ground Magnetic Field Predictions

NASA Astrophysics Data System (ADS)

Honkonen, I. J.; Viljanen, A.; Juusola, L.; Facsko, G.; Vanhamäki, H.

2013-12-01

Space weather can have severe effects even at ground level when Geomagnetically Induced Currents (GIC) disrupt power transmission networks, the worst case being a complete blackout affecting millions of people. The importance of space weather forecasting as well as the need for model improvement and validation has been recognized internationally. The recently concluded GUMICS-4 one year run, in which solar wind observations obtained from OMNIWeb for the period 2002-01-29 to 2003-02-02 were given as input to the model, will allow GUMICS to be validated against observations on an unprecedented scale. The performance of GUMICS can be quantified statistically, as a function of, for example, the solar wind driver, various geomagnetic indices, magnetic local time and other parameters. Here we concentrate on the ability of GUMICS to predict ground magnetic field observations for one year of simulated results. The ground magnetic field predictions are compared to observations of the mainland IMAGE magnetometer stations located at CGM latitudes 54-68 N. Furthermore the GIC derived from ground magnetic field predictions are compared to observations along the natural gas pipeline at Mäntsälä, South Finland. Various metrics are used to objectively evaluate the performance of GUMICS as a function of different parameters, thereby providing significant insight into the space weather forecasting ability of models based on first principles.

In situ observations of Pc1 pearl pulsations by the Van Allen Probes

NASA Astrophysics Data System (ADS)

Paulson, K. W.; Smith, C. W.; Lessard, M. R.; Engebretson, M. J.; Torbert, R. B.; Kletzing, C. A.

2014-03-01

We present in situ observations of Pc1 pearl pulsations using the Van Allen Probes. These waves are often observed using ground-based magnetometers, but are rarely observed by orbiting satellites. With the Van Allen Probes, we have seen at least 14 different pearl pulsation events during the first year of operations. These new in situ measurements allow us to identify the wave classification based on local magnetic field conditions. Additionally, by using two spacecraft, we are able to observe temporal changes in the region of observation. The waves appear to be generated at an overall central frequency, as often observed on the ground, and change polarization from left- to right-handedness as they propagate into a region where they are resonant with the crossover frequency (where R- and L-mode waves have the same phase velocity). By combining both in situ and ground-based data, we have found that the region satisfying electromagnetic ion cyclotron wave generation conditions is azimuthally large while radially narrow. The observation of a similar modulation period on the ground as in the magnetosphere contradicts the bouncing wave packet mechanism of generation.

A Complete Cubesat Magnetometer System Project

NASA Technical Reports Server (NTRS)

Zesta, Eftyhia

2014-01-01

The objective of this work is to provide the center with a fully tested, flexible, low cost, miniaturized science magnetometer system applicable to small satellite programs, like Cubesats, and to rides of opportunity that do not lend themselves to the high integration costs a science magnetometer on a boom necessitates.

Magnetic heading reference

NASA Technical Reports Server (NTRS)

Garner, H. D. (Inventor)

1977-01-01

This invention employs a magnetometer as a magnetic heading reference for a vehicle such as a small aircraft. The magnetometer is mounted on a directional dial in the aircraft in the vicinity of the pilot such that it is free to turn with the dial about the yaw axis of the aircraft. The invention includes a circuit for generating a signal proportional to the northerly turning error produced in the magnetometer due to the vertical component of the earth's magnetic field. This generated signal is then subtracted from the output of the magnetometer to compensate for the northerly turning error.

The MAGSAT vector magnetometer: A precision fluxgate magnetometer for the measurement of the geomagnetic field

NASA Technical Reports Server (NTRS)

Acuna, M. H.; Scearce, C. S.; Seek, J.; Scheifele, J.

1978-01-01

A description of the precision triaxial fluxgate magnetometer to be flown aboard the MAGSAT spacecraft is presented. The instrument covers the range of + or - 64,000 nT with a resolution of + or - 0.5 nT, an intrinsic accuracy of + or - 0.001% of full scale and an angular alignment stability of the order of 2 seconds of arc. It was developed at NASA's Goddard Space Flight Center and represents the state-of-the-art in precision vector magnetometers developed for spaceflight use.

Alignment of a vector magnetometer to an optical prism

DOE PAGES

Dietrich, M. R.; Bailey, K. G.; O’Connor, T. P.

2017-05-12

A method for alignment of a vector magnetometer to a rigidly attached prism is presented. This enables optical comparison of the magnetometer axes to physical surfaces in the apparatus, and thus an absolute determination of the magnetic field direction in space. This is in contrast with more common techniques, which focus on precise determination of the relative angles between magnetometer axes, and so are more suited to measuring differences in the direction of magnetic fields. Here we demonstrate precision better than 500 μrad on a fluxgate magnetometer, which also gives the coil orthogonality errors to a similar precision. As amore » result, the relative sensitivity of the three axes is also determined, with a precision of about 5 ×10 –4.« less

Correcting GOES-R Magnetometer Data for Stray Fields

NASA Technical Reports Server (NTRS)

Carter, Delano; Freesland, Douglas; Tadikonda, Sivakumar; Kronenwetter, Jeffrey; Todirita, Monica; Dahya, Melissa; Chu, Donald

2016-01-01

Time-varying spacecraft magnetic fields, i.e. stray fields, are a problem for magnetometer systems. While constant fields can be removed by calibration, stray fields are difficult to distinguish from ambient field variations. Putting two magnetometers on a long boom and solving for both the ambient and stray fields can help, but this gradiometer solution is more sensitive to noise than a single magnetometer. As shown here for the R-series Geostationary Operational Environmental Satellites (GOES-R), unless the stray fields are larger than the noise, simply averaging the two magnetometer readings gives a more accurate solution. If averaging is used, it may be worthwhile to estimate and remove stray fields explicitly. Models and estimation algorithms to do so are provided for solar array, arcjet and reaction wheel fields.

Design and analysis of control system for VCSEL of atomic interference magnetometer

NASA Astrophysics Data System (ADS)

Zhang, Xiao-nan; Sun, Xiao-jie; Kou, Jun; Yang, Feng; Li, Jie; Ren, Zhang; Wei, Zong-kang

2016-11-01

Magnetic field detection is an important means of deep space environment exploration. Benefit from simple structure and low power consumption, atomic interference magnetometer become one of the most potential detector payloads. Vertical Cavity Surface Emitting Laser (VCSEL) is usually used as a light source in atomic interference magnetometer and its frequency stability directly affects the stability and sensitivity of magnetometer. In this paper, closed-loop control strategy of VCSEL was designed and analysis, the controller parameters were selected and the feedback error algorithm was optimized as well. According to the results of experiments that were performed on the hardware-in-the-loop simulation platform, the designed closed-loop control system is reasonable and it is able to effectively improve the laser frequency stability during the actual work of the magnetometer.

Equatorial ionospheric disturbances over the East African sector during the 2015 St. Patrick's day storm

NASA Astrophysics Data System (ADS)

Olwendo, O. J.; Cesaroni, C.; Yamazaki, Y.; Cilliers, P.

2017-10-01

During solar cycle 24, the St. Patrick's Day storm on 17 March, 2015 was one of the most severe geomagnetic storms. Several research investigations have been done and are still ongoing about this storm since the dynamics of this storm differs on a global scale from one sector to another. This study examines the response of the equatorial ionosphere to the storm in the East African sector. Total electron content (TEC) data from ground stations are used to investigate the evolution of the Equatorial Ionization Anomaly (EIA) during the storm. The TEC observations show a reduced EIA during 18-20 March 2015, consistent with previous studies at other longitudes. Analyses of ground magnetometer data and the thermospheric composition data from the NASA/TIMED satellite reveal that the reduced EIA during the storm can arise from the combined effect of the disturbance dynamo and composition change.

ULF Generation by Modulated Ionospheric Heating

NASA Astrophysics Data System (ADS)

Chang, C.; Labenski, J.; Wallace, T.; Papadopoulos, K.

2013-12-01

Modulated ionospheric heating experiments designed to generate ULF waves using the HAARP heater have been conducted since 2007. Artificial ULF waves in the Pc1 frequency range were observed from space and by ground induction magnetometers located in the vicinity of the heater as well as at long distances. Two distinct generation mechanisms of artificial ULF waves were identified. The first was electroject modulation under geomagnetically disturbed conditions. The second was pressure modulation in the E and F regions of the ionosphere under quiet conditions. Ground detections of ULF waves near the heater included both Shear Alfven waves and Magnetosonic waves generated by electrojet and/or pressure modulations. Distant ULF detections involved Magnetosonic wave propagation in the Alfvenic duct with pressure modulation as the most likely source. Summary of our observations and theoretical interpretations will be presented at the meeting. We would like to acknowledge the support provided by the staff at the HAARP facility during our ULF experiments.

Voyager spacecraft electrostatic discharge testing

NASA Technical Reports Server (NTRS)

Whittlesey, A.; Inouye, G.

1980-01-01

The program of environmental testing undergone by the Voyager spacecraft in order to simulate the transient voltage effects of electrostatic discharges expected in the energetic plasma environment of Jupiter is reported. The testing consists of studies of the electrostatic discharge characteristics of spacecraft dielectrics in a vacuum-chamber-electron beam facility, brief piece part sensitivity tests on such items as a MOSFET multiplexer and the grounding of the thermal blanket, and assembly tests of the magnetometer boom and the science boom. In addition, testing of a complete spacecraft was performed using two arc sources to simulate long and short duration discharge sources for successive spacecraft shielding and grounding improvements. Due to the testing program, both Voyager 1 and Voyager 2 experienced tolerable electrostatic discharge-caused transient anomalies in science and engineering subsystems, however, a closer duplication of the spacecraft environment is necessary to predict and design actual spacecraft responses more accurately.

Simultaneous observation of the poleward expansion of substorm electrojet activity and the tailward expansion of current sheet disruption in the near-earth magnetotail

NASA Technical Reports Server (NTRS)

Lopez, R. E.; Koskinen, H. E. J.; Pulkkinen, T. I.; Bosinger, T.; Mcentire, R. W.; Potemra, T. A.

1993-01-01

A substorm that occurred on 7 June 1985 at 2209 UT for which simultaneous measurements from ground stations and CCE are available is considered. The event occurred during a close conjunction between CCE, the EISCAT magnetometer cross, and the STARE radar, allowing a detailed comparison of satellite and ground-based data. Two discrete activations took place during the first few minutes of this substorm: the expansion phase onset at 2209 UT and an intensification at 2212 UT, corresponding to a poleward expansion of activity. The energetic particle data indicate that the active region of the magnetotail during the 2212 UT intensification was located tailward of the active region at 2209 UT. This is direct evidence for a correspondence between tailward expansion of localized activity in the near-earth magnetotail (current disruption and particle energization) and poleward expansion of activity (electrojet formation) in the ionosphere.

Data Assimilation Results from PLASMON

NASA Astrophysics Data System (ADS)

Jorgensen, A. M.; Lichtenberger, J.; Duffy, J.; Friedel, R. H.; Clilverd, M.; Heilig, B.; Vellante, M.; Manninen, J. K.; Raita, T.; Rodger, C. J.; Collier, A.; Reda, J.; Holzworth, R. H.; Ober, D. M.; Boudouridis, A.; Zesta, E.; Chi, P. J.

2013-12-01

VLF and magnetometer observations can be used to remotely sense the plasmasphere. VLF whistler waves can be used to measure the electron density and magnetic Field Line Resonance (FLR) measurements can be used to measure the mass density. In principle it is then possible to remotely map the plasmasphere with a network of ground-based stations which are also less expensive and more permanent than satellites. The PLASMON project, funded by the EU FP-7 program, is in the process of doing just this. A large number of ground-based observations will be input into a data assimilative framework which models the plasmasphere structure and dynamics. The data assimilation framework combines the Ensemble Kalman Filter with the Dynamic Global Core Plasma Model. In this presentation we will describe the plasmasphere model, the data assimilation approach that we have taken, PLASMON data and data assimilation results for specific events.

Conjugate High Latitude Measurements of Traveling Convection Vortices during Solstice Conditions on 2013/01/09

NASA Astrophysics Data System (ADS)

Xu, Zhonghua; Clauer, C. Robert; Hartinger, Michael; Kim, Hyomin

2016-04-01

The ground magnetic response to a solar wind sudden impulse (SI) on 2013/01/19 produced traveling convection vortices observed in both northern winter and southern summer hemispheres by conjugate magnetometer chains along the 40 degree magnetic meridian. The conjugate measurements permit us to investigate the latitudinal dependence and dependence on interhemispheric conductance asymmetries. This event shows remarkable agreement in the timing and amplitude of the ground magnetic disturbance in both hemispheres, suggesting that the current strength is similar in both hemispheres despite the solstice conductance differences. Using additional observations and simulations, we explore the magnetospheric response to solar wind pressure transients and the resulting coupling to the ionosphere in both hemispheres by a current generation process. The Antarctic instrumentation for this research has been supported by the National Science Foundation through a Major Research Infrastructure (MRI) grant ATM-922979 and grant PLR-1243398 has supported the stations operations and the research.

Real-time positioning technology in horizontal directional drilling based on magnetic gradient tensor measurement

NASA Astrophysics Data System (ADS)

Deng, Guoqing; Yao, Aiguo

2017-04-01

Horizontal directional drilling (HDD) technology has been widely used in Civil Engineering. The dynamic position of the drill bit during construction is one of significant facts determining the accuracy of the trajectory of HDD. A new method now has been proposed to detecting the position of drill bit by measuring the magnetic gradient tensor of the ground solenoid magnetic beacon. Compared with traditional HDD positioning technologies, this new model is much easier to apply with lower request for construction sites and higher positioning efficiency. A direct current (DC) solenoid as a magnetic dipole is placed on ground near the drill bit, and related sensors array which contains four Micro-electromechanical Systems (MEMS ) tri-axial magnetometers, one MEMS tri-axial accelerometer and one MEMS tri-axial gyroscope is set up for measuring the magnetic gradient tensor of the magnetic dipole. The related HDD positioning model has been established and simulation experiments have been carried out to verify the feasibility and reliability of the proposed method. The experiments show that this method has good positioning accuracy in horizontal and vertical direction, and totally avoid the impact of the environmental magnetic field. It can be found that the posture of the magnetic beacon will impact the remote positioning precision within valid positioning range, and the positioning accuracy is higher with longer baseline for limited space in drilling tools. The results prove that the relative error can be limited in 2% by adjusting position of the magnetic beacon, the layers of the enameled coil, the sensitive of magnetometers and the baseline distance. Conclusion can be made that this new method can be applied in HDD positioning with better effect and wider application range than traditional method.

IAR signatures in the ionosphere: Modeling and observations at the Chibis-M microsatellite

NASA Astrophysics Data System (ADS)

Pilipenko, V.; Dudkin, D.; Fedorov, E.; Korepanov, V.; Klimov, S.

2017-02-01

A peculiar feature of geomagnetic variations at middle/low latitudes in the ULF band, just below the fundamental tone of the Schumann resonance, is the occurrence of a multi-band spectral resonant structure, observed by high-sensitivity induction magnetometers during nighttime. The occurrence of such spectral structure was commonly attributed to the Ionospheric Alfvén Resonator (IAR) in the upper ionosphere. Rather surprisingly, while ground observations of the IAR are ubiquitous, there are practically no reports on the IAR signatures from space missions. According to the new paradigm, the multi-band spectral structure excited by a lightning discharge is in fact produced by a regular sequence of an original pulse from a stroke and echo-pulses reflected from the IAR upper boundary. Upon the interaction of initial lightning-generated pulse with the anisotropic lower ionosphere, it partially penetrates into the ionosphere, travels up the ionosphere as an Alfvén pulse, and reflects back from the upper IAR boundary. The superposition of the initial pulse and echo-pulses produces spectra with multiple spectral peaks. Our modeling of Alfvénic pulse propagation in a system with the altitude profile of Alfven velocity modeling the realistic ionosphere has shown that IAR spectral signatures are to be evident only on the ground and above the IAR. Inside the IAR, the superposition of upward and downward propagating pulses produces a more complicated spectral pattern and the IAR spectral signatures deteriorate. We have used electric field data from the low-orbit Chibis-M microsatellite to search for IAR signatures in the ionosphere. We found evidence that the multi-band structure revealed by spectral analysis in the frequency range of interest is indeed the result of a sequence of lightning-produced pulses. According to the proposed conception it seems possible to comprehend why the IAR signatures are less evident in the ionosphere than on the ground.

Analysing Harmonic Motions with an iPhone's Magnetometer

ERIC Educational Resources Information Center

Yavuz, Ahmet; Temiz, Burak Kagan

2016-01-01

In this paper, we propose an experiment for analysing harmonic motion using an iPhone's (or iPad's) magnetometer. This experiment consists of the detection of magnetic field variations obtained from an iPhone's magnetometer sensor. A graph of harmonic motion is directly displayed on the iPhone's screen using the "Sensor Kinetics"…

Autonomous Underwater Munitions and Explosives of Concern Detection System

DTIC Science & Technology

2015-03-01

Field Magnetometer ......................................................................... 19 5.3.2 Fluxgate Compass...through the vehicle control system. Magnetic measurements are sampled at 10 Hz. 5.3.2 Fluxgate Compass Located in the magnetometer module pressure...pitch, and roll) from the fluxgate compass and the total field magnetometer measurements are required for processing into the MagComp compensation

In situ triaxial magnetic field compensation for the spin-exchange-relaxation-free atomic magnetometer.

PubMed

Fang, Jiancheng; Qin, Jie

2012-10-01

The spin-exchange-relaxation-free (SERF) atomic magnetometer is an ultra-high sensitivity magnetometer, but it must be operated in a magnetic field with strength less than about 10 nT. Magnetic field compensation is an effective way to shield the magnetic field, and this paper demonstrates an in situ triaxial magnetic field compensation system for operating the SERF atomic magnetometer. The proposed hardware is based on optical pumping, which uses some part of the SERF atomic magnetometer itself, and the compensation method is implemented by analyzing the dynamics of the atomic spin. The experimental setup for this compensation system is described, and with this configuration, a residual magnetic field of strength less than 2 nT (±0.38 nT in the x axis, ±0.43 nT in the y axis, and ±1.62 nT in the z axis) has been achieved after compensation. The SERF atomic magnetometer was then used to verify that the residual triaxial magnetic fields were coincident with what were achieved by the compensation system.

Polymer encapsulated microcavity optomechanical magnetometer

DOE PAGES

Zhu, Jiangang; Zhao, Guangming; Savukov, Igor; ...

2017-08-21

We demonstrate a magnetometer using polymer encapsulated whispering-gallery-mode microcavity actuated by a micro-magnet. The magnetic field induces force on the micro-magnet causing deformation in the polymer around the microcavity. Subsequently the microcavity detects the change in the refractive index of the polymer resulted from the deformation. This magnetometer works in the frequency range of hertz-to-kilohertz range and achieves a sensitivity of 880 pT/Hz 1/2 at 200 Hz in a micro-scale sensor volume. Polymer encapsulation of the magnetometer and fiber optical connection ensures environmental robustness and practicality of the sensor.

The Magsat precision vector magnetometer

NASA Technical Reports Server (NTRS)

Acuna, M. H.

1980-01-01

This paper examines the Magsat precision vector magnetometer which is designed to measure projections of the ambient field in three orthogonal directions. The system contains a highly stable and linear triaxial fluxgate magnetometer with a dynamic range of + or - 2000 nT (1 nT = 10 to the -9 weber per sq m). The magnetometer electronics, analog-to-digital converter, and digitally controlled current sources are implemented with redundant designs to avoid a loss of data in case of failures. Measurements are carried out with an accuracy of + or - 1 part in 64,000 in magnitude and 5 arcsec in orientation (1 arcsec = 0.00028 deg).

Search Coil vs. Fluxgate Magnetometer Measurements at Interplanetary Shocks

NASA Technical Reports Server (NTRS)

Wilson, L.B., III

2012-01-01

We present magnetic field observations at interplanetary shocks comparing two different sample rates showing significantly different results. Fluxgate magnetometer measurements show relatively laminar supercritical shock transitions at roughly 11 samples/s. Search coil magnetometer measurements at 1875 samples/s, however, show large amplitude (dB/B as large as 2) fluctuations that are not resolved by the fluxgate magnetometer. We show that these fluctuations, identified as whistler mode waves, would produce a significant perturbation to the shock transition region changing the interpretation from laminar to turbulent. Thus, previous observations of supercritical interplanetary shocks classified as laminar may have been under sampled.

All-optical, Three-axis Fiber Laser Magnetometer

DTIC Science & Technology

2012-04-16

into each core using an ultraviolet laser. Measurements of the differences in induced strain between the FBGs enables bending in two dimensions to...housing. This is repeated for multiple inclinations. The difference in strain between two FBGs as a function of rotation for three inclination...angles of 9°, 45°, and 81° is shown in Fig. 10(a). The FBG strain is measured using an interferometric method, and as such, the difference in strain is

An improved Overhauser magnetometer for Earth's magnetic field observation

NASA Astrophysics Data System (ADS)

Fan, Shifang; Chen, Shudong; Zhang, Shuang; Guo, Xin; Cao, Qiong

2016-09-01

Overhauser magnetometer is a kind of high-precision devices for magnetostatic field measurement. It is widely used in geological survey, earth field variations, UXO detection etc. However, the original Overhauser magnetometer JOM-2 shows great shortcomings of low signal to noise ratio (SNR) and high power consumption, which directly affect the performance of the device. In order to increase the sensitivity and reduce power consumption, we present an improved Overhauser magnetometer. Firstly, compared with the original power board which suffers from heavy noise for improper EMC design, an improved power broad with 20mV peak to peak noise is presented in this paper. Then, the junction field effect transistor (JFET) is used as pre-amplifier in our new design, to overcome the higher current noise produced by the original instrumentation amplifier. By adjusting the parameters carefully low noise factor down to 0.5 dB can be obtained. Finally, the new architecture of ARM + CPLD is adopted to replace the original one with DSP+CPLD. So lower power consumption and greater flash memory can be realized. With these measures, an improved Overhauser magnetometer with higher sensitivity and lower power consumption is design here. The experimental results indicate that the sensitivity of the improved Overhauser magnetometer is 0.071nT, which confirms that the new magnetometer is sensitive to earth field measurement.

Magnetometer-only attitude and angular velocity filtering estimation for attitude changing spacecraft

NASA Astrophysics Data System (ADS)

Ma, Hongliang; Xu, Shijie

2014-09-01

This paper presents an improved real-time sequential filter (IRTSF) for magnetometer-only attitude and angular velocity estimation of spacecraft during its attitude changing (including fast and large angular attitude maneuver, rapidly spinning or uncontrolled tumble). In this new magnetometer-only attitude determination technique, both attitude dynamics equation and first time derivative of measured magnetic field vector are directly leaded into filtering equations based on the traditional single vector attitude determination method of gyroless and real-time sequential filter (RTSF) of magnetometer-only attitude estimation. The process noise model of IRTSF includes attitude kinematics and dynamics equations, and its measurement model consists of magnetic field vector and its first time derivative. The observability of IRTSF for small or large angular velocity changing spacecraft is evaluated by an improved Lie-Differentiation, and the degrees of observability of IRTSF for different initial estimation errors are analyzed by the condition number and a solved covariance matrix. Numerical simulation results indicate that: (1) the attitude and angular velocity of spacecraft can be estimated with sufficient accuracy using IRTSF from magnetometer-only data; (2) compared with that of RTSF, the estimation accuracies and observability degrees of attitude and angular velocity using IRTSF from magnetometer-only data are both improved; and (3) universality: the IRTSF of magnetometer-only attitude and angular velocity estimation is observable for any different initial state estimation error vector.

Demonstration of an Enhanced Vertical Magnetic Gradient System for UXO

DTIC Science & Technology

2008-12-01

fluxgate magnetometers , data recording console, laser altimeter, and acoustic altimeters were tested to ensure proper operation and performance. The VG...Simultaneous Electromagnetic Induction and Magnetometer System WAA wide area assessment ACKNOWLEDGEMENTS We wish to express our sincere...sensors. The benefits of vertical gradient (VG) configurations in magnetometer systems are common knowledge, and these configurations are routinely

A Low Frequency Electromagnetic Sensor for Underwater Geo-Location

DTIC Science & Technology

2011-05-01

used a set of commercially available fluxgate magnetometers to measure the magnetic field gradients associated with a magnetic dipole transmitter...insight into the operational capabilities of commercial fluxgate sensors. Figure 42. Applied Physics Systems 1540 magnetometer ...a magnetic field gradient receiver array. Highest quality gradient estimates were achieved with three vector magnetometers equally spaced and

Feasibility Study for an Autonomous UAV -Magnetometer System -- Final Report on SERDP SEED 1509:2206

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roelof Versteeg; Mark McKay; Matt Anderson

2007-09-01

Large areas across the United States are potentially contaminated with UXO, with some ranges encompassing tens to hundreds of thousands of acres. Technologies are needed which will allow for cost effective wide area scanning with 1) near 100 % coverage and 2) near 100 % detection of subsurface ordnance or features indicative of subsurface ordnance. The current approach to wide area scanning is a multi-level one, in which medium altitude fixed wing optical imaging is used for an initial site assessment. This assessment is followed with low altitude manned helicopter based magnetometry followed by surface investigations using either towed geophysicalmore » sensor arrays or man portable sensors. In order to be effective for small UXO detection, the sensing altitude for magnetic site investigations needs to be on the order of 1 – 3 meters. These altitude requirements means that manned helicopter surveys will generally only be feasible in large, open and relatively flat terrains. While such surveys are effective in mapping large areas relatively fast there are substantial mobilization/demobilization, staffing and equipment costs associated with these surveys (resulting in costs of approximately $100-$150/acre). Surface towed arrays provide high resolution maps but have other limitations, e.g. in their ability to navigate rough terrain effectively. Thus, other systems are needed allowing for effective data collection. An UAV (Unmanned Aerial Vehicle) magnetometer platform is an obvious alternative. The motivation behind such a system is that it would be safer for the operators, cheaper in initial and O&M costs, and more effective in terms of site characterization. However, while UAV data acquisition from fixed wing platforms for large (> 200 feet) stand off distances is relatively straight forward, a host of challenges exist for low stand-off distance (~ 6 feet) UAV geophysical data acquisition. The objective of SERDP SEED 1509:2006 was to identify the primary challenges associated with a low stand off distance autonomous UAV magnetometer platform and to investigate whether these challenges can be resolved successfully such that a successful UAV magnetometer platform can be constructed. The primary challenges which were identified and investigated include: 1. The feasibility of assembling a payload package which integrates magnetometers, accurate positioning systems (DGPS, height above ground measurement), obstacle avoidance systems, power infrastructure, communications and data storage as well as auxiliary flight controls 2. The availability of commercial UAV platforms with autonomous flight capability which can accommodate this payload package 3. The feasibility of integrating obstacle avoidance controls in UAV platform control 4. The feasibility of collecting high quality magnetic data in the vicinity of an UAV.« less

Global MHD Test Particle Simulations of 10 MeV Radiation Belt Electrons During Sudden Storm Commencement

DTIC Science & Technology

2007-09-22

9 0 , a n d I t o 2 m n h t o b d i c r a l al h e o w q u o i l p t hthe SC lectic ieldpule ispreominntl in he 1 to 2 months to be discemable at the...correlation with sharp increase in the H -component, ground B dx(A, magnetometer perturbation which is the signature of an SSC event. The March 1991...Parametric study of shock- Press, W. H ., B . P. Flannery, S. A. Teukolsky, and W. T. Vetterling (1992),induced transport and energization of relativistic

Multi-Parameter Wireless Monitoring and Telecommand of a Rocket Payload: Design and Implementation

NASA Astrophysics Data System (ADS)

Pamungkas, Arga C.; Putra, Alma A.; Puspitaningayu, Pradini; Fransisca, Yulia; Widodo, Arif

2018-04-01

A rocket system generally consists of two parts, the rocket motor and the payload. The payload system is built of several sensors such as accelerometer, gyroscope, magnetometer, and also a surveillance camera. These sensors are used to monitor the rocket in a three-dimensional axis which determine its attitude. Additionally, the payload must be able to perform image capturing in a certain distance using telecommand. This article is intended to describe the design and also the implementation of a rocket payload which has attitude monitoring and telecommand ability from the ground control station using a long-range wireless module Digi XBee Pro 900 HP.

Sq Currents and Neutral Winds

NASA Astrophysics Data System (ADS)

Yamazaki, Y.

2015-12-01

The relationship between ionospheric dynamo currents and neutral winds is examined using the Thermosphere Ionosphere Mesosphere Electrodynamic General Circulation Model (TIME-GCM). The simulation is run for May and June 2009 with variable neutral winds but with constant solar and magnetospheric energy inputs, which ensures that day-to-day changes in the solar quiet (Sq) current system arise only from lower atmospheric forcing. The intensity and focus position of the simulated Sq current system exhibit large day-to-day variability, as is also seen in ground magnetometer data. We show how the day-to-day variation of the Sq current system relate to variable winds at various altitudes, latitudes, and longitudes.

Novel Handheld Magnetometer Probe Based on Magnetic Tunnelling Junction Sensors for Intraoperative Sentinel Lymph Node Identification

PubMed Central

Cousins, A.; Balalis, G. L.; Thompson, S. K.; Forero Morales, D.; Mohtar, A.; Wedding, A. B.; Thierry, B.

2015-01-01

Using magnetic tunnelling junction sensors, a novel magnetometer probe for the identification of the sentinel lymph node using magnetic tracers was developed. Probe performance was characterised in vitro and validated in a preclinical swine model. Compared to conventional gamma probes, the magnetometer probe showed excellent spatial resolution of 4.0 mm, and the potential to detect as few as 5 μg of magnetic tracer. Due to the high sensitivity of the magnetometer, all first-tier nodes were identified in the preclinical experiments, and there were no instances of false positive or false negative detection. Furthermore, these preliminary data encourage the application of the magnetometer probe for use in more complex lymphatic environments, such as in gastrointestinal cancers, where the sentinel node is often in close proximity to other non-sentinel nodes, and high spatial resolution detection is required. PMID:26038833

Detection of magnetic moment in thin films with a home-made vibrating sample magnetometer

NASA Astrophysics Data System (ADS)

Jordán, D.; González-Chávez, D.; Laura, D.; León Hilario, L. M.; Monteblanco, E.; Gutarra, A.; Avilés-Félix, L.

2018-06-01

This paper explores the optimization of an array of pick-up coils in a home-made vibrating sample magnetometer for the detection of magnetic moment in thin films. Sensitivity function of a 4-coils Mallinson configuration was numerically studied for the determination of the physical dimensions that enhance the sensitivity of the magnetometer. By performing numerical simulations using the Biot-Savart law combined with the principle of reciprocity we were able to determine the maximum values of sensitivity and the influence of the separation of the coils on the sensitivity function. After the optimization of the pick-up coils, the vibrating sample magnetometer was able to detect the magnetic moment of a 100 nm-thickness Fe19 Ni81 magnetic thin film along and perpendicular to the in-plane anisotropy easy axis. The implemented vibrating sample magnetometer is able to detect changes in the magnetic moment of ∼ 2 × 10-4 emu.

Developement of a Fluxgate Magnetometer for the KITSAT-3 Satellite

NASA Astrophysics Data System (ADS)

Hwang, S. H.; Lee, D. H.; Min, K. W.; Shin, Y. H.; Choi, C. R.; Nobuhito, O.

1997-12-01

The magnetometer is one of the most important payloads of scientific satellites to monitor the near-earth space environment. The electromagnetic variations of the space environment can be observed with the electric and magnetic field measurements. In practice, it is well known that the measurement of magnetic fields needs less technical complexities than that of electric fields in space. Therefore the magnetometer has long been recognized as one of the basic payloads for the scientific satellites. In this paper, we discuss the scientific fluxgate magnetometer which will be on board the KITSAT-3. The main circuit design of the present magnetometer is based on that of KISAT-1 and -2 but its facilities have been re-designed to improve the resolution to about 5nT for scientific purpose. The calibration and noise level test of this circuit have been performed at the laboratory of the Tierra Tecnica company in Japan.

Miniature Free-Flying Magnetometer Utilizing System-On-A-Chip Technology

NASA Technical Reports Server (NTRS)

Eyre, F. B.; Blaes, B. R.

2001-01-01

Four Free-Flying Magnetometers (FFMs), developed at the Jet Propulsion Laboratory (JPL) for the Enstrophy mission, were successfully deployed from the payload of a sounding rocket launched from Poker Flats, Alaska on February 11, 1999. The FFMs functioned successfully by synchronously measuring the vector magnetic field at 4 points separate from the payload and at relative distances up to 3 km, and communicated their data, in bursts, to the ground. This is the first time synchronized in-situ multipoint measurements of the Earth's magnetic field utilizing miniature spin-stabilized "sensorcraft" have been performed. The data they provided have enabled, for the first time, the direct measure of field-aligned current density and are enabling new science by determining the fine-scale structure of the currents in the Earth's ionosphere involved in the production of aurora. These proof-of-concept "hockey puck" (80 mm diameter, 38 mm height, 250 gram mass) FFMs were built using off-the-shelf commercial, industrial, and military grade surface-mount electronic components. Radiation-hard electronics was not required for the Enstrophy mission's short sub-orbital flight. The successful design, implementation, and flight demonstration of this 1st generation FFM design has provided a solid base for further development of a 2nd generation FFM design for planetary science applications. A reliable ultra-miniature radiation-hard 2nd-generation FFM utilizing System-On-A-Chip (SOAC) technologies is proposed. This design would be targeted for long-term planetary missions to investigate magnetospheric field configurations in regions having small-scale structure and to separate spatial and temporal variations. A fleet of short-lived (expendable) FFMs would be deployed into a targeted region to gather multiprobe vector magnetic field data. The FFMs would be ejected from a parent spacecraft at a speed of a few m/sec and would cover spatial volumes of order tens of kilometers for times of order one hour. The parent spacecraft would carry a sufficient number of FFMs for multiple deployments. Additional information is contained in the original extended abstract.

Advanced UXO Discrimination using Magnetometry: Understanding Remanent Magnetization

DTIC Science & Technology

2009-09-01

moments of steel samples. The MRIP comprises six three-component fluxgate magnetometers symmetrically distributed around a rotating sample holder. Samples...comprises six three- component fluxgate magnetometers symmetrically distributed around a rotating sample holder. Samples are placed on the holder... fluxgate magnetometers symmetrically distributed around a rotating sample holder. Samples are placed on the holder and are slowly spun through two

Compact, Low-Noise Magnetic Sensor with Fluxgate (DC) and Induction (AC) Modes of Operation

DTIC Science & Technology

2009-07-01

induction sensor and the fluxgate magnetometer . ......................................... 2 Figure 3.1 - Impulse response of a 4” long coil (#6...Block diagram of the Year 2, Task 2 fluxgate magnetometer . ................................... 6 Figure 3.3 - FIS-prototype magnetic-field...and demonstrated an innovative dual-mode, fluxgate -induction sensor (FIS) that combines a fluxgate magnetometer and an electromagnetic (EM) induction

ArchaeoMapper Beta Test Report

DTIC Science & Technology

2008-06-01

instruments (Geoscan, Bartington, GSSI, etc.) are you familiar with? The Geoscan Fluxgate Magnetometer and the Goescan Resistance Meter 2. What software do...Magnetometry - Geoscan magnetometer , RM 15 Geoscan resistance meter, and GSSI SIR 20 Radar 2. What software do you typically use to process your...Geoscan, Bartington, GSSI, etc.) are you familiar with? Magnetometry - Geoscan magnetometer , RM 15 Geoscan resistance meter, and GSSI SIR 20 Radar

Detection of NMR signals with a radio-frequency atomic magnetometer.

PubMed

Savukov, I M; Seltzer, S J; Romalis, M V

2007-04-01

We demonstrate detection of proton NMR signals with a radio-frequency (rf) atomic magnetometer tuned to the NMR frequency of 62 kHz. High-frequency operation of the atomic magnetometer makes it relatively insensitive to ambient magnetic field noise. We obtain magnetic field sensitivity of 7 fT/Hz1/2 using only a thin aluminum shield. We also derive an expression for the fundamental sensitivity limit of a surface inductive pick-up coil as a function of frequency and find that an atomic rf magnetometer is intrinsically more sensitive than a coil of comparable size for frequencies below about 50 MHz.

Magnetometer bias determination and attitude determination for near-earth spacecraft

NASA Technical Reports Server (NTRS)

Lerner, G. M.; Shuster, M. D.

1979-01-01

A simple linear-regression algorithm is used to determine simultaneously magnetometer biases, misalignments, and scale factor corrections, as well as the dependence of the measured magnetic field on magnetic control systems. This algorithm has been applied to data from the Seasat-1 and the Atmosphere Explorer Mission-1/Heat Capacity Mapping Mission (AEM-1/HCMM) spacecraft. Results show that complete inflight calibration as described here can improve significantly the accuracy of attitude solutions obtained from magnetometer measurements. This report discusses the difficulties involved in obtaining attitude information from three-axis magnetometers, briefly derives the calibration algorithm, and presents numerical results for the Seasat-1 and AEM-1/HCMM spacecraft.

Analysing harmonic motions with an iPhone’s magnetometer

NASA Astrophysics Data System (ADS)

Yavuz, Ahmet; Kağan Temiz, Burak

2016-05-01

In this paper, we propose an experiment for analysing harmonic motion using an iPhone’s (or iPad’s) magnetometer. This experiment consists of the detection of magnetic field variations obtained from an iPhone’s magnetometer sensor. A graph of harmonic motion is directly displayed on the iPhone’s screen using the Sensor Kinetics application. Data from this application was analysed with Eureqa software to establish the equation of the harmonic motion. Analyses show that the use of an iPhone’s magnetometer to analyse harmonic motion is a practical and effective method for small oscillations and frequencies less than 15-20 Hz.

Multi-Instrument Analysis of a Traveling Convection Vortex Event on July 24, 1996 Coordinated with the Polar UVI

NASA Technical Reports Server (NTRS)

Sitar, R. J.; Clauer, C. R.; Baker, J. B.; Ridley, A. J.; Cumnock, J.; Germany, G. A.; Spann, J. F., Jr.; Brittnacher, M. J.; Parks, G. K.

1998-01-01

We present the analysis of a coordinated set of observations from the POLAR Ultraviolet Imager (UVI), ground magnetometers, incoherent scatter radar, solar wind monitors, DMSP and GOES satellites, focused on a traveling convection vortex (TCV) event on 24th July 1996. Starting at approximately 10:48 UT, around magnetometers in Greenland and northern Canada observe pulsations consistent with the passing overhead of a series of alternating TCV filed-aligned current pairs. Azimuthal scans by the Sondrestrom incoherent scatter radar located near Kangerlussuaq (formerly Sondrestrom), Greenland, at this time show strong modulation in the strength and direction of ionospheric plasma flow. The magnetometer pulsations grow in magnitude over the next hour, peaking in intensity at 11:39 UT, at which time images form the UVI instrument show a localized intensification of auroral emissions over central and western Greenland. Subsequent images show the intensification grow in strength and propagate westward (tailward) until approximately 11:58 UT at which time the intensification fades. These observations are consistent with the westward passage of two pairs of moderately intense TCVs over central Greenland followed by a third very intense TCV pair. The intensification of auroral emissions at 11:39 UT is associated with the trailing vortex of the third TCV pair, thought to be the result of an upward field aligned current. The modulated flow observed by the radar is the result of the strong electric fields associated with the impulsive TCV related field aligned current systems as they pass through the field of view of the radar. Measurements of the solar wind from the V;IND and IMP-8 spacecraft suggest that a pressure change may be responsible for triggering the first two pairs of TCVS, and that a subsequent sudden change in the orientation of the interplanetary magnetic field may have produced the intensification of the third TCV pair and the associated auroral brightening. Magnetometer data from the GOES satellite located over the eastern United States at geostationary orbit is consistent with a series of field-aligned moving tailward past the satellite. DMSP particle data indicated that the TCVs occur on field lines which map to the boundary plasma sheet (BPS).

Preliminary results for an aeromagnetic survey flown over Italy using the HALO (High Altitude and LOng range) research aircraft

NASA Astrophysics Data System (ADS)

Lesur, V.; Gebler, A.; Schachtschneider, R.

2012-12-01

In June 2012 the GEOHALO mission was flown over Italy using the high altitude and long-range German research aircraft HALO (Gulfstream jet - G550). One goal of the mission was to demonstrate the feasibility of using geodetic and geophysical instrumentation on such fast flying aircraft. Several types of data were acquired including gravity, GNSS signals (reflectometry, spectrometry and occultation), laser altimetry and magnetic data. The magnetic data were collected through two independent acquisition chains placed inside under-wing containers. Each chain included a total intensity cesium magnetometer, a three-component fluxgate magnetometer, several temperature censors and a digitizer. Magnetic and temperature data were collected at a 10 Hz sampling rate. Seven parallel profiles, each around 1000 km long, were flown over the Apennine peninsula from north-west to south-east. The flight altitude was about 3500 m and the survey line spacing around 40 km. These long profiles were complemented by four crossing profiles, and a repeated flight line at a higher altitude (approx. 10500 m). The ground speed during the flight was generally around 125 m/s (450 km/h). The output from the first steps of the magnetic data processing will be shown. The measured magnetic data appear to be consistent with the expected signal.

Pi2 Pulsations During Extremely Quiet Geomagnetic Condition: Van Allen Probe Observations

NASA Astrophysics Data System (ADS)

Ghamry, Essam

2017-06-01

A ultra low frequency (ULF) wave, Pi2, has been reported to occur during periods of extremely quiet magnetospheric and solar wind conditions. And no statistical study on the Pi2 has been performed during extremely quiet conditions, using satellite observations to the author’s knowledge. Also Pi2 pulsations in the space fluxgate magnetometers near perigee failed to attract scientist’s attention previously. In this paper, Pi2 pulsations detected by the Van Allen probe satellites (VAP-A & VAP-B) were investigated statistically. During the period from October 2012 to December 2014, ninety six Pi2 events were identified using VAP when Kp = 0 while using Kakioka (KAK, L = 1.23) as a reference ground station. Seventy five events had high coherence between VAP-Bz and H components at KAK station. As a result, it was found that 77 % of the events had power spectra between 5 and 12 mHz, which differs from the regular Pi2 band range of from 6.7 to 25 mHz. In addition, it was shown that it is possible to observe Pi2 pulsations from space fluxgate magnetometers near perigee. Twenty two clean Pi2 pulsations were found where L < 4 and four examples of Pi2 oscillations at different L shells are presented in this paper.

Seismo-magnetic observations aboard the upcoming Chinese CSES satellite

NASA Astrophysics Data System (ADS)

Schwingenschuh, Konrad; Magnes, Werner; Xuhui, Shen; Wang, Jindong; Pollinger, Andreas; Hagen, Christian; Lammegger, Roland; Ellmeier, Michaela; Prattes, Gustav; Eichelberger, Hans U.; Wolbang, Daniel; Boudjada, Mohammed Y.; Besser, Bruno P.; Rozhnoi, Alexander A.; Zhang, Tielong; Delva, Magda; Jernej, Irmgard; Aydogar, Özer

2017-04-01

One objective of the upcoming Chinese Seismo-Electromagnetic Satellite (CSES) mission is the observation of seismo-magnetic phenomena aboard CSES. Several hypothesis exist in order to explain the influence of seismic phenomena on magnetic field variations in the atmosphere and in the ionosphere. The so called microfracture electrification (Molchanov and Hayakawa, 1998) proposes the generation of a broad band electric-magnetic signal which is low-pass filtered by the crustal and atmospheric/ionospheric conductivity. Depending on the environmental conductivity sigma and on the permeability mu (Prattes et al., 2008) the electromagnetic field fluctuations with the frequency omega can propagate approximately d_skin. (d_skin) = sqrt(2/(mu*sigma*omega)) We present the sensitivity of the CSES scalar dark state magnetometer (Schwingenschuh et al., 2016) after the final tests and compare it with seismo-magnetic ULF model results using various earthquake parameters. References: Prattes, G. et al.: Multi-point ground-based ULF magnetic field observations in Europe during seismic active periods in 2004 and 2005, Nat. Hazards Earth Syst. Sci., 8, 501-507, 2008 Molchanov, O. and Hayakawa, M.: On the generation mechanism of ULF seismogenic electromagnetic emissions, Phys. of the Earth and Planet. Int., 105, 201-210, 1998 Schwingenschuh, K. et al.: Study of earthquakes and related phenomena using a satellite scalar magnetometer, Geophysical Research Abstracts, Vol. 18, EGU2016-8448, 2016

Stereo and Solar Cycle 24

NASA Technical Reports Server (NTRS)

Kaise,r Michael L.

2008-01-01

The twin STEREO spacecrafi, launched in October 2006, are in heliocentric orbits near 4 AU with one spacecraft (Ahead) leading Earth in its orbit around the Sun and the other (Behind) trailing Earth. As viewed from the Sun, the STEREO spacecraft are continually separating from one another at about 45 degrees per year with Earth biseding the angle. At present, th@spaser=raft are a bit more than 45 degrees apart, thus they are able to each 'vie@ ground the limb's of the Sun by about 23 degrees, corresponding to about 1.75 days of solar rotation. Both spameraft contain an identical set of instruments including an extreme ultraviolet imager, two white light coronagraphs, tws all-sky imagers, a wide selection of energetic particle detectors, a magnetometer and a radio burst tracker. A snapshot of the real time data is continually broadcast to NOW-managed ground stations and this small stream of data is immediately sent to the STEREO Science Center and converted into useful space weather data within 5 minutes of ground receipt. The resulting images, particle, magnetometer and radio astronomy plots are available at j g i t , : gAs timqe conting ues ijnto . g solar cycle 24, the separation angle becomes 90 degrees in early 2009 and 180 degrees in early 201 1 as the activity heads toward maximum. By the time of solar maximum, STEREO will provide for the first time a view of the entire Sun with the mronagraphs and e*reme ultraviolet instruments. This view wilt allow us to follow the evolution of active regions continuously and also detect new active regions long before they pose a space weather threat to Earth. The in situ instruments will be able to provide about 7 days advanced notice of co-rotating structures in the solar wind. During this same intewal near solar maximum, the wide-angle imagers on STEREB will both be ;able to view EarlCP-dirsted CMEs in their plane-oPsky. When combined with Eat-lhorbiting assets available at that time, it seems solar cycle 24 will mark a great increase in our ability to understand and predict space weather.

Advanced helium magnetometer for space applications

NASA Technical Reports Server (NTRS)

Slocum, Robert E.

1987-01-01

The goal of this effort was demonstration of the concepts for an advanced helium magnetometer which meets the demands of future NASA earth orbiting, interplanetary, solar, and interstellar missions. The technical effort focused on optical pumping of helium with tunable solid state lasers. We were able to demonstrate the concept of a laser pumped helium magnetometer with improved accuracy, low power, and sensitivity of the order of 1 pT. A number of technical approaches were investigated for building a solid state laser tunable to the helium absorption line at 1083 nm. The laser selected was an Nd-doped LNA crystal pumped by a diode laser. Two laboratory versions of the lanthanum neodymium hexa-aluminate (LNA) laser were fabricated and used to conduct optical pumping experiments in helium and demonstrate laser pumped magnetometer concepts for both the low field vector mode and the scalar mode of operation. A digital resonance spectrometer was designed and built in order to evaluate the helium resonance signals and observe scalar magnetometer operation. The results indicate that the laser pumped sensor in the VHM mode is 45 times more sensitive than a lamp pumped sensor for identical system noise levels. A study was made of typical laser pumped resonance signals in the conventional magnetic resonance mode. The laser pumped sensor was operated as a scalar magnetometer, and it is concluded that magnetometers with 1 pT sensitivity can be achieved with the use of laser pumping and stable laser pump sources.

Demonstration of Helicopter Multi-Towed Array Detection System (MTADS) Magnetometry Technology at Pueblo Precision Bombing Range #2, Colorado

DTIC Science & Technology

2008-08-28

for aircraft pitch measurement Fluxgate magnetometer 10 RS232- ASCII SerialDevice.fluxgate Provides redundant aircraft attitude measurement...Figure 28. Filtered, ’final’ magnetometer data taken at high altitude. ......................................................... 43 LIST OF TABLES...flight. The magnetometer data can be analyzed to extract either distributions of magnetic anomalies (which can be further used to locate and bound

TOROID II

DTIC Science & Technology

2009-01-01

three axis fluxgate magnetometer , CMOS sun and star sensors, and a Kalman filter. The work and tasks that have been accomplished on the TOROID... magnetometer . The problem was found to be a missing ferrite bead which connects the 12V power supply to the op-amps which are used to appropriately...establish an overall operational timeline for TOROID. Testing and calibration was performed on the three-axis magnetometer which is primary attitude

Detection of J-coupling using atomic magnetometer

DOEpatents

Ledbetter, Micah P.; Crawford, Charles W.; Wemmer, David E.; Pines, Alexander; Knappe, Svenja; Kitching, John; Budker, Dmitry

2015-09-22

An embodiment of a method of detecting a J-coupling includes providing a polarized analyte adjacent to a vapor cell of an atomic magnetometer; and measuring one or more J-coupling parameters using the atomic magnetometer. According to an embodiment, measuring the one or more J-coupling parameters includes detecting a magnetic field created by the polarized analyte as the magnetic field evolves under a J-coupling interaction.

Low-noise magnetometer based on inductance modulation in high-critical-temperature superconductor coil

NASA Astrophysics Data System (ADS)

Enpuku, Keiji; Matsuo, Masaaki; Yoshida, Yujiro; Yamashita, Shigeya; Sasayama, Teruyoshi; Yoshida, Takashi

2018-06-01

We developed a magnetometer based on inductance modulation of a coil made from a high-critical-temperature superconducting material. The coil inductance was modulated over time via a modulation current applied to a magnetic wire that was inserted into the coil. The magnetic field was then converted into a signal voltage using this time-dependent inductance. The relationship between magnetometer performance and the modulation current conditions was studied. Under appropriate conditions, the magnetometer had responsivity of 885 V/T. The magnetic field noise was 1.3 pT/Hz1/2 in the white noise region and 5.6 pT/Hz1/2 at f = 1 Hz.

Magnetogama: an open schematic magnetometer

NASA Astrophysics Data System (ADS)

Wahyudi; Khakhim, Nurul; Kuntoro, Tri; Mardiatno, Djati; Rakhman, Afif; Setyo Handaru, Anas; Akhmad Mufaqih, Adien; Marwan Irnaka, Theodosius

2017-09-01

Magnetogama is an open schematic hand-assembled fluxgate magnetometer. Compared to another magnetometer, Magnetogama has more benefit concerning its price and its ease of use. Practically Magnetogama can be utilized either in land or attached to an unmanned aerial vehicle (UAV). Magnetogama was designed to give open access to a cheap and accurate alternative to magnetometer sensor. Therefore it can be used as a standard design which is directly applicable to the low-budget company or education purposes. Schematic, code and several verification tests were presented in this article ensuring its reproducibility. Magnetogama has been tested with two kind of tests: a comparison with two nearest observatories at Learmonth (LRM) and Kakadu (KDU) and the response of magnetic substance.

Lunar surface magnetometer experiment

NASA Technical Reports Server (NTRS)

Dyal, P.; Parkin, C. W.; Sonett, C. P.

1972-01-01

The Apollo 15 lunar-surface magnetometer (LSM) is one of a network of magnetometers that have been deployed on the moon to study intrinsic remanent magnetic fields and global magnetic response of the moon to large-scale solar and terrestrial magnetic fields. From these field measurements, properties of the lunar interior such as magnetic permeability, electrical conductivity, and temperature can be calculated. In addition, correlation with solar-wind-spectrometer data allows study of the the solar-wind plasma interaction with the moon and, in turn, investigation of the resulting absorption of gases and accretion of an ionosphere. These physical parameters and processes determined from magnetometer measurements must be accounted for by comprehensive theories of origin and evolution of the moon and solar system.

The Z3 model of Saturns magnetic field and the Pioneer 11 vector helium magnetometer observations

NASA Technical Reports Server (NTRS)

Connerney, J. E. P.; Acuna, M. H.; Ness, N. F.

1984-01-01

Magnetic field observations obtained by the Pioneer 11 vector helium magnetometer are compared with the Z(sub 3) model magnetic field. These Pioneer 11 observations, obtained at close-in radial distances, constitute an important and independent test of the Z(sub 3) zonal harmonic model, which was derived from Voyager 1 and Voyager 2 fluxgate magnetometer observations. Differences between the Pioneer 11 magnetometer and the Z(sub 3) model field are found to be small (approximately 1%) and quantitatively consistent with the expected instrumental accuracy. A detailed examination of these differences in spacecraft payload coordinates shows that they are uniquely associated with the instrument frame of reference and operation. A much improved fit to the Pioneer 11 observations is obtained by rotation of the instrument coordinate system about the spacecraft spin axis by 1.4 degree. With this adjustment, possibly associated with an instrumental phase lag or roll attitude error, the Pioneer 11 vector helium magnetometer observations are fully consistent with the Voyager Z(sub 3) model.

Magnetogate: using an iPhone magnetometer for measuring kinematic variables

NASA Astrophysics Data System (ADS)

Kağan Temiz, Burak; Yavuz, Ahmet

2016-01-01

This paper presents a method to measure the movement of an object from specific locations on a straight line using an iPhone’s magnetometer. In this method, called ‘magnetogate’, an iPhone is placed on a moving object (in this case a toy car) and small neodymium magnets are arranged at equal intervals on one side of a straight line. The magnetometer sensor of the iPhone is switched on and then the car starts moving. The iPhone’s magnetometer is stimulated throughout its movement along a straight line. A ‘sensor Kinetics’ application on the iPhone saves the magnetic stimulations and produces a graph of the changing magnetic field near the iPhone. At the end of motion, data from the magnetometer is interpreted and peaks on the graph are detected. Thus, position-time changes can be analysed and comments about the motion of the object can be made. The position, velocity and acceleration of the object can be easily measured with this method.

Magnetic Sensors with Picotesla Magnetic Field Sensitivity at Room Temperature

DTIC Science & Technology

2008-06-01

such small fields require cryogenic cooling such as SQUID sensors, require sophisticated detection systems such as atomic magnetometers and fluxgate ... magnetometers , or have large size and poor low frequency performance such as coil systems. [3-7] The minimum detectable field (the field noise times...Kingdon, "Development of a Combined EMI/ Magnetometer Sensor for UXO Detection," Proc. Symposium on the Applications of Geophysics to Environmental and

Munitions Detection Using Unmanned Underwater Vehicles Equipped with Advanced Sensors

DTIC Science & Technology

2012-06-29

buried target. The RTG is a small passive magnetic sensor using fluxgate magnetometers measuring 3- orthogonal magnetic-field vector components at 3...surveys. Figure 6 shows the RTG magnetic sensor in both an open (showing the fluxgate magnetometers ) and enclosed state (mode for integration onto...7.6 Real-time Tracking Gradiometer (RTG) System The RTG is a small passive magnetic sensor using fluxgate magnetometers measuring 3- orthogonal

Rapid Damage Assessment. Volume I. Methodology for Selecting Repair Area of Ordnance-Damaged Pavements.

DTIC Science & Technology

1980-09-01

this system be given no further consideration. 14AGNETOMETER TECHNIQUES Four types of magnetometers are commonly in use today: fluxgate , proton...that are cumbersome to operate and less accurate than fluxgate and proton mag- netometers. The proton magnetometer is also gradually replacing the... fluxgate magnetometer because of its greater sensitivity (I gamma or better), absolute accuracy, nonmoving parts, and its ability Lo measure absolute

Intelligent magnetometer with photoelectric sampler

NASA Astrophysics Data System (ADS)

Wang, Defang; Xu, Yan; Zhu, Minjun

1991-08-01

The magnetometer described in this paper introduces a photoelectric sampler and a single-chip microcomputer, thus eliminating the error that is not eliminated in the analog circuit. The application of the photoelectric segregator and the voltage-to-frequency convertor have suppressed the interference significantly. According to the requirement of measuring the magnetic field, the function of automatic searching the latching is added. The intelligent magnetometer has higher accuracy and good temperature stability.

Vectorized magnetometer for space applications using electrical readout of atomic scale defects in silicon carbide

NASA Astrophysics Data System (ADS)

Cochrane, Corey J.; Blacksberg, Jordana; Anders, Mark A.; Lenahan, Patrick M.

2016-11-01

Magnetometers are essential for scientific investigation of planetary bodies and are therefore ubiquitous on missions in space. Fluxgate and optically pumped atomic gas based magnetometers are typically flown because of their proven performance, reliability, and ability to adhere to the strict requirements associated with space missions. However, their complexity, size, and cost prevent their applicability in smaller missions involving cubesats. Conventional solid-state based magnetometers pose a viable solution, though many are prone to radiation damage and plagued with temperature instabilities. In this work, we report on the development of a new self-calibrating, solid-state based magnetometer which measures magnetic field induced changes in current within a SiC pn junction caused by the interaction of external magnetic fields with the atomic scale defects intrinsic to the semiconductor. Unlike heritage designs, the magnetometer does not require inductive sensing elements, high frequency radio, and/or optical circuitry and can be made significantly more compact and lightweight, thus enabling missions leveraging swarms of cubesats capable of science returns not possible with a single large-scale satellite. Additionally, the robustness of the SiC semiconductor allows for operation in extreme conditions such as the hot Venusian surface and the high radiation environment of the Jovian system.

A dumbbell-shaped hybrid magnetometer operating in DC-10 kHz

NASA Astrophysics Data System (ADS)

Shi, Hongyu; Wang, Yanzhang; Chen, Siyu; Lin, Jun

2017-12-01

This study is motivated by the need to design a hybrid magnetometer operating in a wide-frequency band from DC to 10 kHz. To achieve this objective, a residence times difference fluxgate magnetometer (RTDFM) and an induction magnetometer (IM) have been integrated into a compact form. The hybrid magnetometer has a dumbbell-shaped structure in which the RTDFM transducer is partially inserted into the tube cores of the IM. Thus, the sensitivity of the RTDFM is significantly improved due to the flux amplification. The optimal structure, which has maximum sensitivity enhancement, was obtained through FEM analysis. To validate the theoretical analysis, the optimal hybrid magnetometer was manufactured, and its performance was evaluated. The device has a sensitivity of 45 mV/nT at 1 kHz in IM mode and 0.38 μs/nT in RTDFM mode, which is approximately 3.45 times as large as that of the single RTDFM structure. Furthermore, to obtain a lower noise performance in the entire frequency band, two operation modes switch at the cross frequency (0.16 Hz) of their noise levels. The noise level is 30 pT/√Hz in RTDFM mode and 0.07 pT/√Hz at 1 kHz in IM mode.

A dumbbell-shaped hybrid magnetometer operating in DC-10 kHz.

PubMed

Shi, Hongyu; Wang, Yanzhang; Chen, Siyu; Lin, Jun

2017-12-01

This study is motivated by the need to design a hybrid magnetometer operating in a wide-frequency band from DC to 10 kHz. To achieve this objective, a residence times difference fluxgate magnetometer (RTDFM) and an induction magnetometer (IM) have been integrated into a compact form. The hybrid magnetometer has a dumbbell-shaped structure in which the RTDFM transducer is partially inserted into the tube cores of the IM. Thus, the sensitivity of the RTDFM is significantly improved due to the flux amplification. The optimal structure, which has maximum sensitivity enhancement, was obtained through FEM analysis. To validate the theoretical analysis, the optimal hybrid magnetometer was manufactured, and its performance was evaluated. The device has a sensitivity of 45 mV/nT at 1 kHz in IM mode and 0.38 μs/nT in RTDFM mode, which is approximately 3.45 times as large as that of the single RTDFM structure. Furthermore, to obtain a lower noise performance in the entire frequency band, two operation modes switch at the cross frequency (0.16 Hz) of their noise levels. The noise level is 30 pT/√Hz in RTDFM mode and 0.07 pT/√Hz at 1 kHz in IM mode.

Vectorized magnetometer for space applications using electrical readout of atomic scale defects in silicon carbide

PubMed Central

Cochrane, Corey J.; Blacksberg, Jordana; Anders, Mark A.; Lenahan, Patrick M.

2016-01-01

Magnetometers are essential for scientific investigation of planetary bodies and are therefore ubiquitous on missions in space. Fluxgate and optically pumped atomic gas based magnetometers are typically flown because of their proven performance, reliability, and ability to adhere to the strict requirements associated with space missions. However, their complexity, size, and cost prevent their applicability in smaller missions involving cubesats. Conventional solid-state based magnetometers pose a viable solution, though many are prone to radiation damage and plagued with temperature instabilities. In this work, we report on the development of a new self-calibrating, solid-state based magnetometer which measures magnetic field induced changes in current within a SiC pn junction caused by the interaction of external magnetic fields with the atomic scale defects intrinsic to the semiconductor. Unlike heritage designs, the magnetometer does not require inductive sensing elements, high frequency radio, and/or optical circuitry and can be made significantly more compact and lightweight, thus enabling missions leveraging swarms of cubesats capable of science returns not possible with a single large-scale satellite. Additionally, the robustness of the SiC semiconductor allows for operation in extreme conditions such as the hot Venusian surface and the high radiation environment of the Jovian system. PMID:27892524

Vectorized magnetometer for space applications using electrical readout of atomic scale defects in silicon carbide.

PubMed

Cochrane, Corey J; Blacksberg, Jordana; Anders, Mark A; Lenahan, Patrick M

2016-11-28

Magnetometers are essential for scientific investigation of planetary bodies and are therefore ubiquitous on missions in space. Fluxgate and optically pumped atomic gas based magnetometers are typically flown because of their proven performance, reliability, and ability to adhere to the strict requirements associated with space missions. However, their complexity, size, and cost prevent their applicability in smaller missions involving cubesats. Conventional solid-state based magnetometers pose a viable solution, though many are prone to radiation damage and plagued with temperature instabilities. In this work, we report on the development of a new self-calibrating, solid-state based magnetometer which measures magnetic field induced changes in current within a SiC pn junction caused by the interaction of external magnetic fields with the atomic scale defects intrinsic to the semiconductor. Unlike heritage designs, the magnetometer does not require inductive sensing elements, high frequency radio, and/or optical circuitry and can be made significantly more compact and lightweight, thus enabling missions leveraging swarms of cubesats capable of science returns not possible with a single large-scale satellite. Additionally, the robustness of the SiC semiconductor allows for operation in extreme conditions such as the hot Venusian surface and the high radiation environment of the Jovian system.

A 3He-129Xe co-magnetometer probed by a Rb magnetometer with Ramsey-pulse technique

NASA Astrophysics Data System (ADS)

Sheng, Dong; Kabcenell, Aaron; Romalis, Michael

2013-05-01

We report the recent progress in development of a new kind of co-magnetometer, benifiting from both the long spin coherence time of a noble gas and a highly sensitive alkali metal magnetometer. Due to the Fermi-contact interaction between alkali metal electron spin and noble gas nuclear spin the effective magnetization of the noble gas is enhanced by a factor of 6 to 600, allowing near quantum-limited detection of nuclear spins. Collisions between polarized alkali atoms and noble gas also introduce a large shift to the nuclear spin precession frequency. We reduce this effect by using Ramsey pulse techniques to measure the noble gas spin precession frequency ``in the dark'' by turning off the pumping laser between Ramsey pulses. A furthur reduction of the back-hyperpolarization from the noble gas can be achieved by controlling the cell temperature on short time scale. We showed that a 3He-129Xe Ramsey co-magnetometer is effective in cancelling fluctuations of external magnetic fields and gradients and developed cells with sufficient 129Xe T2 time without surface coatings. The new co-magnetometer has potential applications for many precision measurements, such as searches for spin-gravity couplings, electric dipole moments, and nuclear spin gyroscopes. Supported by DARPA.

Development of Search-Coil Magnetometer for Ultra Low Frequency (ULF) Wave Observations at Jang Bogo Station in Antarctica

NASA Astrophysics Data System (ADS)

Lee, J. K.; Shin, J.; Kim, K. H.; Jin, H.; Kim, H.; Kwon, J.; Lee, S.; Jee, G.; Lessard, M.

2016-12-01

A ground-based bi-axial search-coil magnetometer (SCM) has been devloped for observation of time-varying magnetic fields (dB/dt) in the Ultra Low Frequency (ULF) range (a few mHz up to 5 Hz) to understand magnetosphere-ionosphere coupling processes. The SCM consists of magnetic sensors, analog electronics, cables and data acquisition system (DAQ). The bi-axial magnetic sensor has coils of wire wound around a mu-metal cores, each of which measures magnetic field pulsations in the horizontal components, geomagnetic north-south and east-west, respectively. The analog electronics is designed to control the cut-off frequency of the instrument and to amplify detected signals. The DAQ has a 16 bit analog to digital converter (ADC) at the user defined rate of 10 Hz. It is also equipped with the Global Positioning System (GPS) and Network Time Protocol (NTP) for time synchronization and accuracy. We have carried out in-lab performance tests (e.g., frequency response, noise level, etc) using a magnetically shielded case and a field-test in a magnetically quiet location in South Korea. During the field test, a ULF Pi 2 event has been observed clearly. We also confirmed that it was a substorm activity from a fluxgate magnetometer data at Mineyama (35°57.3'N, 135°05'E, geographic). The SCM will be installed and operated at Jang Bogo Antarctic Research Station (74°37.4'S, 164°13.7'E, geographic) on Dec. 2016. The geomagnetic latitude of the station is similar to that of the US McMurdo station (77°51'S, 166°40'E, geographic), both of which are typically near the cusp region. Thus, we expect that the SCM can provide useful information to understand ULF wave propagation characteristics.

A Small Autonomous Unmanned Aerial Vehicle, Ant-Plane 4, for aeromagnetic survey

NASA Astrophysics Data System (ADS)

Funaki, M.; Tanabe, S.; Project, A.

2007-05-01

Autonomous unmanned aerial vehicles (UAV) are expected to use in Antarctica for geophysical research due to economy and safety operations. We have developed the technology of small UAVwith autonomous navigation referred to GPS and onboard magnetometer, meteorolgical devices and digital camera under the Ant-Plane project. The UAV focuses on operation for use in the summer season at coastal area in Antarctica; higher temperature than -15C under calm wind. In case of Ant-Plane 4, it can fly continuously more than 500 km, probably more than 1000 km, although the flight in Antarcitca has not succeeded The UAV of FRP is pusher type drone consisting of 2.6m span and 2.0m length with 2-cycles and 2-cylinder 86cc gasoline engine (7.2 HP) navigated. The maximum takeoff weight is 25kg including 1kg of payload. Cruising distance 500 km at speed of 130 km/h using 10 litter of fuel. The UAV is controlled by radio telemeter within 5km from a ground station and autonomous navigation referred to GPS latitude and longitude, pitot tube speed and barometer altitude. The magnetometer system consists of a 3-component magneto-resistant magnetometer (MR) sensor (Honeywell HMR2300), GPS and data logger. Three components of magnetic field, latitude, longitude, altitude, the number of satellite and time are recorded every second during 6 hours. The sensitivity of the magnetometer is 7 nT and we use a total magnetic field intensity for magnetic analysis due to unknown direction of heading of the plane. We succeeded in long distant flight to 500km with magnetometer by Ant-Plane 4 collaborated with Geoscience Australia, in March 2006. The survey was performed in the area 10kmx10km at Kalgoorlie, Western Australia. The magnetic data are obtained from 41 courses (250m in interval) of EW direction. The altitude of the flight was 900m from sea level and 500m from the runway. MR-magnetometer sensor was installed at the tip of a FRP pipe of 1m length, and the pipe was fixed to the head of the plane in order to reduce the plane magnetization. After 4 hours 14 minutes from the takeoff, the 500km flight was accomplished and the magnetic data were stored in the data logger. The straight flight course was almost consistent with the way point course, but the course was drastically disturbed when the plane was turning. The resolution of magnetic field decreased to 30nT, when the plane flew to the tail wind. However, it is worse against the head wind. Obtained anomaly pattern was compared with the magnetic anomaly pattern published by Geoscience Australia. Both patterns were essentially consistent, although a part of pattern in the head wind flights was not resemble. Ant-Plane 4 flew up to 5700 m in altitude with aerosol counter, thermometer and hygrometer at northern part of Japan. A drastic change of temperature, humidity and particle number was observed at the inversion layer of atmosphere. Consequently we conclude that the small drone Ant-Plane 4 can be used for geophysical research. We are making effort to develop Ant-Plane for more simple assemblage and more easy operation.

Next Generation HeliMag UXO Mapping Technology

DTIC Science & Technology

2009-10-01

fluxgate magnetometer is used to allow for aeromagnetic compensation of the data as well as to provide redundant attitude information. 2.1.4 Telemetry...sensor operator from the helicopter. Based on a survey design study , the number of magnetometers was increased from 7 to 13, decreasing the across... magnetometers on a Kevlar reinforced boom mounted on a Bell 206L helicopter. The objectives of this demonstration were too:  Improve data acquisition speeds

Report on the HAARP 2008 Winter Campaign Focusing on Artificial Ionospheric Irregularities

DTIC Science & Technology

2008-07-31

Figure Bl. Magnetic field variations recorded by the fluxgate magnetometer 30 Figure B2. Composite ionogram showing the variation of the reflection...variation was monitored by the Fluxgate Magnetometer . The density irregularities were monitored by the Ionosonde. 20:00 Preliminary Results The...magnetic field variations in three directions (H, D, and Z) recorded by the fluxgate magnetometer from UTC 20:00 to 04:00 are shown in the plots of

Contrasting O/X-mode Heater Effects on O-Mode Sounding echo and the Generation of Magnetic Pulsations

DTIC Science & Technology

2010-01-06

Micropulsation [10] The induced magnetic field variation was monitored by the fluxgate magnetometer located at Gakona, AK. The 1 sec resolution data...minutes on and 1 minute off, were explored. The experiments were monitored using the digisonde and magnetometer located at the HAARP facility. The...were explored. The experiments were monitored using the digisonde and magnetometer located at the HAARP facility. The results show that the

Demonstration of Helicopter Multi-Sensor Towed Array Detection System (MTADS) Magnetometry Technology at Victorville Precision Bombing Range, California

DTIC Science & Technology

2008-09-12

measurement Fluxgate magnetometer 10 RS232- ASCII SerialDevice.fluxgate Provides redundant aircraft attitude measurement Acoustic altimeters 10 Analog...primarily by terrain, vegetation, and structural inhibitions to safe low-altitude flight. The magnetometer data can be analyzed to extract either...to validate the results of the magnetometer survey. ESTCP Victorville PBR WAA Final Report December 2008 Sky Research, Inc. 2 1.2. Objectives of

Shipboard Elevator Magnetic Sensor Development. Phase I, Laboratory Investigations.

DTIC Science & Technology

1981-08-19

greater detail. The principles studied were those of the flux-meter and the flux-gate magnetometer . Of these two, the flux-gate magnetometer principle was...Abstract (Continued) Flux-gate magnetometers continuously sense the component of a stationary or slowly varying magnetic field along a chosen axis. The...distance of the sensor from the target’s line of travel, while precisely indicating displacements along the line. The modes of detection include level

Optical Magnetometer Incorporating Photonic Crystals

NASA Technical Reports Server (NTRS)

Kulikov, Igor; Florescu, Lucia

2007-01-01

According to a proposal, photonic crystals would be used to greatly increase the sensitivities of optical magnetometers that are already regarded as ultrasensitive. The proposal applies, more specifically, to a state-of-the-art type of quantum coherent magnetometer that exploits the electromagnetically-induced-transparency (EIT) method for determining a small change in a magnetic field indirectly via measurement of the shift, induced by that change, in the hyperfine levels of resonant atoms exposed to the field.

Participation in the Cluster Magnetometer Consortium for the Cluster Mission

NASA Technical Reports Server (NTRS)

Kivelson, Margaret

1997-01-01

Prof. M. G. Kivelson (UCLA) and Dr. R. C. Elphic (LANL) are Co-investigators on the Cluster Magnetometer Consortium (CMC) that provided the fluxgate magnetometers and associated mission support for the Cluster Mission. The CMC designated UCLA as the site with primary responsibility for the inter-calibration of data from the four spacecraft and the production of fully corrected data critical to achieving the mission objectives. UCLA was also charged with distributing magnetometer data to the U.S. Co-investigators. UCLA also supported the Technical Management Team, which was responsible for the detailed design of the instrument and its interface. In this final progress report we detail the progress made by the UCLA team in achieving the mission objectives.

THREE-COMPONENT BOREHOLE MAGNETOMETER PROBE FOR MINERAL INVESTIGATIONS AND GEOLOGIC RESEARCH.

USGS Publications Warehouse

Scott, James H.; Olson, Gary G.

1985-01-01

A small-diameter three-component fluxgate magnetometer probe with gyroscopic and inclinometer orientation has been developed to meet U. S. Geological Survey design and performance specifications for measurement of the direction and intensity of the Earth's magnetic field in vertical and inclined boreholes. The orthogonal fluxgate magnetometer elements have a measurement resolution of 10 nanoteslas (nT) and a range of plus or minus 80,000 nT. The gyroscope has an effective resolution of one degree, and the orthogonal inclinometers, 0. 1 degree. The magnetometer probe has been field tested in several holes drilled through volcanic rocks in Nevada. Results indicate that reversals of polarization can be detected, and some rock units in this area appear to be characterized by unique magnetic signatures.

Design and Analyses of a MEMS Based Resonant Magnetometer

PubMed Central

Ren, Dahai; Wu, Lingqi; Yan, Meizhi; Cui, Mingyang; You, Zheng; Hu, Muzhi

2009-01-01

A novel design of a MEMS torsional resonant magnetometer based on Lorentz force is presented and fabricated. The magnetometer consists of a silicon resonator, torsional beam, excitation coil, capacitance plates and glass substrate. Working in a resonant condition, the sensor’s vibration amplitude is converted into the sensing capacitance change, which reflects the outside magnetic flux-density. Based on the simulation, the key structure parameters are optimized and the air damping effect is estimated. The test results of the prototype are in accordance with the simulation results of the designed model. The resolution of the magnetometer can reach 30 nT. The test results indicate its sensitivity of more than 400 mV/μT when operating in a 10 Pa vacuum environment. PMID:22399981

Cryogenic High-Sensitivity Magnetometer

NASA Technical Reports Server (NTRS)

Day, Peter; Chui, Talso; Goodstein, David

2005-01-01

A proposed magnetometer for use in a cryogenic environment would be sensitive enough to measure a magnetic-flux density as small as a picogauss (10(exp -16) Tesla). In contrast, a typical conventional flux-gate magnetometer cannot measure a magnetic-flux density smaller that about 1 microgauss (10(exp -10) Tesla). One version of this device, for operation near the low end of the cryogenic temperature range, would include a piece of a paramagnetic material on a platform, the temperature of which would be controlled with a periodic variation. The variation in temperature would be measured by use of a conventional germanium resistance thermometer. A superconducting coil would be wound around the paramagnetic material and coupled to a superconducting quantum interference device (SQUID) magnetometer.

Assessing and Ensuring GOES-R Magnetometer Accuracy

NASA Technical Reports Server (NTRS)

Carter, Delano R.; Todirita, Monica; Kronenwetter, Jeffrey; Chu, Donald

2016-01-01

The GOES-R magnetometer subsystem accuracy requirement is 1.7 nanoteslas (nT). During quiet times (100 nT), accuracy is defined as absolute mean plus 3 sigma. During storms (300 nT), accuracy is defined as absolute mean plus 2 sigma. Error comes both from outside the magnetometers, e.g. spacecraft fields and misalignments, as well as inside, e.g. zero offset and scale factor errors. Because zero offset and scale factor drift over time, it will be necessary to perform annual calibration maneuvers. To predict performance before launch, we have used Monte Carlo simulations and covariance analysis. Both behave as expected, and their accuracy predictions agree within 30%. With the proposed calibration regimen, both suggest that the GOES-R magnetometer subsystem will meet its accuracy requirements.

Report of geomagnetic pulsation indices for space weather applications

USGS Publications Warehouse

Xu, Z.; Gannon, Jennifer L.; Rigler, Erin J.

2013-01-01

The phenomenon of ultra-low frequency geomagnetic pulsations was first observed in the ground-based measurements of the 1859 Carrington Event and has been studied for over 100 years. Pulsation frequency is considered to be “ultra” low when it is lower than the natural frequencies of the plasma, such as the ion gyrofrequency. Ultra-low frequency pulsations are considered a source of noise in some geophysical analysis techniques, such as aeromagnetic surveys and transient electromagnetics, so it is critical to develop near real-time space weather products to monitor these geomagnetic pulsations. The proper spectral analysis of magnetometer data, such as using wavelet analysis techniques, can also be important to Geomagnetically Induced Current risk assessment.

Optical characterization of antirelaxation coatings

NASA Astrophysics Data System (ADS)

Tsvetkov, S.; Gateva, S.; Cartaleva, S.; Mariotti, E.; Nasyrov, K.

2018-03-01

Antirelaxation coatings (ARC) are used in optical cells containing alkali metal vapor to reduce the depolarization of alkali atoms after collisions with the cell walls. The long-lived ground state polarization is a basis for development of atomic clocks, magnetometers, quantum memory, slow light experiments, precision measurements of fundamental symmetries etc. In this work, a simple method for measuring the number of collisions of the alkali atoms with the cell walls without atomic spin randomization (Nasyrov et al., Proc. SPIE (2015)) was applied to characterize the AR properties of two PDMS coatings prepared from different solutions in ether (PDMS 2% and PDMS 5%). We observed influence of the light-induced atomic desorption (LIAD) on the AR properties of coatings.

PhoneSat: Ground Testing of a Phone-Based Prototype Bus

NASA Technical Reports Server (NTRS)

Felix, Carmen; Howard, Benjamin; Reyes, Matthew; Snarskiy, Fedor; Hickman, Ryan; Boshuizen, Christopher; Marshall, William

2010-01-01

Most of the key capabilities that are requisite of a satellite bus are housed in today's smart phones. PhoneSat refers to an initiative to build a ground-based prototype vehicle that could all the basic functionality of a satellite, including attitude control, using a smart Phone as its central hardware. All components used were also low cost Commercial off the Shelf (COTS). In summer 2009, an initial prototype was created using the LEGO Mindstorm toolkit demonstrating simple attitude control. Here we report on a follow up initiative to design, build and test a vehicle based on the Google s smart phone Nexus One. The report includes results from initial thermal-vacuum chamber tests and low altitude sub-orbital rocket flights which show that, at least for short durations, the Nexus One phone is able to withstand key aspects of the space environment without failure. We compare the sensor data from the Phone's accelerometers and magnetometers with that of an external microelectronic inertial measurement unit.

The vertical propagation of disturbances triggered by seismic waves of the 11 March 2011 M9.0 Tohoku earthquake over Taiwan

NASA Astrophysics Data System (ADS)

Liu, J. Y.; Chen, C. H.; Sun, Y. Y.; Chen, C. H.; Tsai, H. F.; Yen, H. Y.; Chum, J.; Lastovicka, J.; Yang, Q. S.; Chen, W. S.; Wen, S.

2016-02-01

In this paper, concurrent/colocated measurements of seismometers, infrasonic systems, magnetometers, HF-CW (high frequency-continuous wave) Doppler sounding systems, and GPS receivers are employed to detect disturbances triggered by seismic waves of the 11 March 2011 M9.0 Tohoku earthquake. No time delay between colocated infrasonic (i.e., super long acoustic) waves and seismic waves indicates that the triggered acoustic and/or gravity waves in the atmosphere (or seismo-traveling atmospheric disturbances, STADs) near the Earth's surface can be immediately activated by vertical ground motions. The circle method is used to find the origin and compute the observed horizontal traveling speed of the triggered infrasonic waves. The speed of about 3.3 km/s computed from the arrival time versus the epicentral distance suggests that the infrasonic waves (i.e., STADs) are mainly induced by the Rayleigh waves. The agreements in the travel time at various heights between the observation and theoretical calculation suggest that the STADs triggered by the vertical motion of ground surface caused by the Tohoku earthquake traveled vertically from the ground to the ionosphere with speed of the sound in the atmosphere over Taiwan.

Quantifying the In-Flight Yaw, Pitch, and Roll of a Semi-Rigidly Mounted Potassium Vapour Magnetometer Suspended Under a Heavy-Lift Multi-Rotor UAV and its Impact on Data Quality

NASA Astrophysics Data System (ADS)

Walter, C. A.; Braun, A.; Fotopoulos, G.

2017-12-01

Research is being conducted to develop an Unmanned Aerial System (UAS) that is capable of reliably and efficiently collecting high resolution, industry standard magnetic data (magnetic data with a fourth difference of +/- 0.05 nT) via an optically pumped vapour magnetometer. The benefits of developing a UAS with these capabilities include improvements in the resolution of localized airborne surveys (2.5 km by 2.5 km) and the ability to conduct 3D magnetic gradiometry surveys in the observation gap evident between traditional terrestrial and manned airborne magnetic surveys (surface elevation up to 120 m). Quantifying the extent of an optically pumped vapour magnetometer's 3D orientation variations, while in-flight and suspended under a UAS, is a significant advancement to existing knowledge as optically pumped magnetometers have an orientation-dependent (to the primary magnetic field vector) process for measuring the magnetic field. This study investigates the orientation characteristics of a GEM Systems potassium vapour magnetometer, GSMP-35U, while semi-rigidly suspended 3 m under a DJI S900, heavy-lift multi-rotor UAV (Unmanned Aerial Vehicle) during an airborne surveying campaign conducted Northeast of Thunder Bay, Ontario, Canada. A nine degrees of freedom IMU (Inertial Measurement Unit), the Adafruit GY-80, was used to quantify the 3D orientation variations (yaw, pitch and roll) of the magnetic sensor during flight. The orientation and magnetic datasets were indexed and linked with a date and time stamp (within 1 ms) via a Raspberry Pi 2, acting as an on-board computer and data storage system. Analysing the two datasets allowed for the in-flight orientation variations of the potassium vapour magnetometer to be directly compared with the gathered magnetic and signal quality data of the magnetometer. The in-flight orientation characteristics of the magnetometer were also quantified for a range of air-speeds and flight maneuvers throughout the survey. Overall, this study validates that maintaining magnetometer yaw, pitch and roll variations within quantified limits (+/- 5 degrees yaw, +/- 10 degrees pitch, +/- 10 degrees roll) during flight can yield reliable and repeatable industry standard magnetic measurements at an increased spatial resolution over manned airborne surveys.

Performance metrics for state-of-the-art airborne magnetic and electromagnetic systems for mapping and detection of unexploded ordnance

NASA Astrophysics Data System (ADS)

Doll, William E.; Bell, David T.; Gamey, T. Jeffrey; Beard, Les P.; Sheehan, Jacob R.; Norton, Jeannemarie

2010-04-01

Over the past decade, notable progress has been made in the performance of airborne geophysical systems for mapping and detection of unexploded ordnance in terrestrial and shallow marine environments. For magnetometer systems, the most significant improvements include development of denser magnetometer arrays and vertical gradiometer configurations. In prototype analyses and recent Environmental Security Technology Certification Program (ESTCP) assessments using new production systems the greatest sensitivity has been achieved with a vertical gradiometer configuration, despite model-based survey design results which suggest that dense total-field arrays would be superior. As effective as magnetometer systems have proven to be at many sites, they are inadequate at sites where basalts and other ferrous geologic formations or soils produce anomalies that approach or exceed those of target ordnance items. Additionally, magnetometer systems are ineffective where detection of non-ferrous ordnance items is of primary concern. Recent completion of the Battelle TEM-8 airborne time-domain electromagnetic system represents the culmination of nearly nine years of assessment and development of airborne electromagnetic systems for UXO mapping and detection. A recent ESTCP demonstration of this system in New Mexico showed that it was able to detect 99% of blind-seeded ordnance items, 81mm and larger, and that it could be used to map in detail a bombing target on a basalt flow where previous airborne magnetometer surveys had failed. The probability of detection for the TEM-8 in the blind-seeded study area was better than that reported for a dense-array total-field magnetometer demonstration of the same blind-seeded site, and the TEM-8 system successfully detected these items with less than half as many anomaly picks as the dense-array total-field magnetometer system.

Vectorial atomic magnetometer based on coherent transients of laser absorption in Rb vapor

NASA Astrophysics Data System (ADS)

Lenci, L.; Auyuanet, A.; Barreiro, S.; Valente, P.; Lezama, A.; Failache, H.

2014-04-01

We have designed and tested an atomic vectorial magnetometer based on the analysis of the coherent oscillatory transients in the transmission of resonant laser light through a Rb vapor cell. We show that the oscillation amplitudes at the Larmor frequency and its first harmonic are related through a simple formula to the angles determining the orientation of the magnetic field vector. The magnetometer was successfully applied to the measurement of the ambient magnetic field.

Magnetic Test Facility - Sensor and Coil Calibrations

DTIC Science & Technology

2013-08-01

amplitude of signals induced into the sensor. 2.1.1.2 Fluxgate magnetometers Fluxgate sensors consist of a ferromagnetic core, around which drive and sense...kHz range to be measured. Fluxgate magnetometers do not have a lower limit to their fre- quency response, and hence can be used to measure...placed within a larger triaxial coil which is used in conjunction with a fluxgate magnetometer to cancel earth’s field at the cen- tre of the coil. A

Evaluation of Airborne Remote Sensing Techniques for Predicting the Distribution of Energetic Compounds on Impact Areas

DTIC Science & Technology

2007-08-01

GPS) antennas. A fluxgate magnetometer is mounted in the forward assembly to compensate for the magnetic signature of the aircraft. A laser...recorded digitally on the ORAGS™ console (Figure 5) inside the helicopter in a binary format. The magnetometers are sampled at a 1200-Hz sample rate and...GPS. Accurate positioning requires a correction for this lag. Time lags among the magnetometers , fluxgate , and GPS signals were measured by a

Enhancement and Utilization of Airborne Magnetometry for the Detection, Characterization, and Identification of Unexploded Ordance (UXO)

DTIC Science & Technology

2007-07-01

measurement system is based on four GPS antennas rather than a fluxgate magnetometer measurement used in previous generation systems. For the ORAGS...hardware 1 $36,500 Orientation system 1 $16,600 Fluxgate magnetometer 1 $5,300 Navigation system 1 $5,200 Laser altimeter 1 $7,300 Data...1 iii LIST OF FIGURES Page Figure 1. Schematic for the ORAGS-Arrowhead Airborne Total Field Magnetometer System Developed for this Project

Asymmetric planar gradiometer for rejection of uniform ambient magnetic noise

DOEpatents

Dantsker, Eugene; Clarke, John

2000-01-01

An asymmetric planar gradiometer for use in making biomagnetic measurements. The gradiometer is formed from a magnetometer which is inductively-coupled to the smaller of two connected loops patterned in a superconducting film which form a flux transformer. The magnetometer is based on a SQUID formed from a high T.sub.c superconducting material. The flux transformer and magnetometer may be formed on separate substrates, allowing the baseline to be increased relative to presently available devices.

Spaced-based search coil magnetometers

NASA Astrophysics Data System (ADS)

Hospodarsky, George B.

2016-12-01

Search coil magnetometers are one of the primary tools used to study the magnetic component of low-frequency electromagnetic waves in space. Their relatively small size, mass, and power consumption, coupled with a good frequency range and sensitivity, make them ideal for spaceflight applications. The basic design of a search coil magnetometer consists of many thousands of turns of wire wound on a high permeability core. When a time-varying magnetic field passes through the coil, a time-varying voltage is induced due to Faraday's law of magnetic induction. The output of the coil is usually attached to a preamplifier, which amplifies the induced voltage and conditions the signal for transmission to the main electronics (usually a low-frequency radio receiver). Search coil magnetometers are usually used in conjunction with electric field antenna to measure electromagnetic plasma waves in the frequency range of a few hertz to a few tens of kilohertzs. Search coil magnetometers are used to determine the properties of waves, such as comparing the relative electric and magnetic field amplitudes of the waves, or to investigate wave propagation parameters, such as Poynting flux and wave normal vectors. On a spinning spacecraft, they are also sometimes used to determine the background magnetic field. This paper presents some of the basic design criteria of search coil magnetometers and discusses design characteristics of sensors flown on a number of spacecraft.

Design and analysis of miniature tri-axial fluxgate magnetometer

NASA Astrophysics Data System (ADS)

Zhi, Menghui; Tang, Liang; Qiao, Donghai

2017-02-01

The detection technology of weak magnetic field is widely used in Earth resource survey and geomagnetic navigation. Useful magnetic field information can be obtained by processing and analyzing the measurement data from magnetic sensors. A miniature tri-axial fluxgate magnetometer is proposed in this paper. This miniature tri-axial fluxgate magnetometer with ring-core structure has a dynamic range of the Earth’s field ±65,000 nT, resolution of several nT. It has three independent parts placed in three perpendicular planes for measuring three orthogonal magnetic field components, respectively. A field-programmable gate array (FPGA) is used to generate stimulation signal, analog-to-digital (A/D) convertor control signal, and feedback digital-to-analog (D/A) control signal. Design and analysis details are given to improve the dynamic range, sensitivity, resolution, and linearity. Our prototype was measured and compared with a commercial standard Magson fluxgate magnetometer as a reference. The results show that our miniature fluxgate magnetometer can follow the Magson’s change trend well. When used as a magnetic compass, our prototype only has ± 0.3∘ deviation compared with standard magnetic compass.

The Z3 model of Saturn's magnetic field and the Pioneer 11 vector helium magnetometer observations

NASA Technical Reports Server (NTRS)

Connerney, J. E. P.; Acuna, M. H.; Ness, N. F.

1984-01-01

Magnetic field observations obtained by the Pioneer 11 vector helium magnetometer are compared with the Z(sub 3) model magnetic field. These Pioneer 11 observations, obtained at close-in radial distances, constitute an important and independent test of the Z(sub 3) zonal harmonic model, which was derived from Voyager 1 and Voyager 2 fluxgate magnetometer observations. Differences between the Pioneer 11 magnetometer and the Z(sub 3) model field are found to be small (approximately 1 percent) and quantitatively consistent with the expected instrumental accuracy. A detailed examination of these differences in spacecraft payload coordinates shows that they are uniquely associated with the instrument frame of reference and operation. A much improved fit to the Pioneer 11 observations is obtained by rotation of the instrument coordinate system about the spacecraft spin axis by 1.4 degree. With this adjustment, possibly associated with an instrumental phase lag or roll attitude error, the Pioneer 11 vector helium magnetometer observations are fully consistent with the Voyager Z(sub 3) model.

Comparison between the Juno Earth flyby magnetic measurements and the magnetometer package on the IRIS solar observatory

NASA Astrophysics Data System (ADS)

Merayo, J. M.; Connerney, J. E.; Joergensen, J. L.; Dougherty, B.

2013-12-01

In October 2013 the NASA's Juno New Frontier spacecraft will perform an Earth Flyby Gravity Assist. During this flyby, Juno will reach an altitude of about 600 km and the magnetometer experiment will measure the magnetic field with very high precision. In June 2013 the NASA's IRIS solar observatory was successfully launched. IRIS uses a very fine guiding telescope in order to maintain a high pointing accuracy, assisted by a very high accuracy star tracker and a science grade vector magnetometer. IRIS was placed into a Sun-synchronous orbit at about 600 km altitude by a Pegasus rocket from the Vandenberg Air Force Base in California. This platform will also allow to performing measurements of the Earth's magnetic field with very high precision, since it carries similar instrumentation as on the Swarm satellites (star trackers and magnetometer). The data recorded by the Juno magnetic experiment and the IRIS magnetometer will bring a very exciting opportunity for comparing the two experiments as well as for determining current structures during the flyby.

CrowdMag - Crowdsourcing magnetic data

NASA Astrophysics Data System (ADS)

Nair, M. C.; Boneh, N.; Chulliat, A.

2014-12-01

In the CrowdMag project, we explore whether digital magnetometers built in modern mobile phones can be used as scientific instruments to measure Earth's magnetic field. Most modern mobile phones have digital magnetometers to orient themselves. A phone's magnetometer measures three components of the local magnetic field with a typical sensitivity of about 150 to 600 nanotesla (nT). By combining data from vector magnetometers and accelerometers, phone's orientation is determined. Using phone's Internet connection, magnetic data and location are sent to a central server. At the server, we check quality of the magnetic data from all users and make the data available to the public as aggregate maps. We have two long-term goals. 1) Develop near-real-time models of Earth's time changing magnetic field by reducing man-made noise from crowdsourced data and combining it with geomagnetic data from other sources. 2) Improving accuracy of magnetic navigation by mapping magnetic noise sources (for e.g. power transformer and iron pipes). Key challenges to this endeavor are the low sensitivity of the phone's magnetometer and the noisy environment within and surrounding the phone. URL : http://www.ngdc.noaa.gov/geomag/crowdmag.shtml

The UOSAT magnetometer experiment

NASA Technical Reports Server (NTRS)

Acuna, M. H.

1982-01-01

The magnetometer aboard the University of Surrey satellite (UOSAT) and its associated electronics are described. The basic fluxgate magnetometer employed has a dynamic range of plus or minus 8000 nT with outputs digitized by a 12-bit successive approximation A-D converter having a resolution of plus or minus 2 nT. Noise in the 3-13 Hz bandwidth is less than 1 nT. A bias field generator extends the dynamic range to plus or minus 64,000 nT with quantization steps of 8000 nT. The magnetometer experiment is expected to provide information on the secular variation of the geomagnetic field, and the decay rate of the dipole term. Special emphasis will be placed on the acquisition of real time and memory data over the poles which can be correlated with that from Magsat.

Development of New Research-Quality Low-Resource Magnetometers for Small Satellites

NASA Technical Reports Server (NTRS)

Moldwin, Mark; Hunter, Roger C.; Baker, Christopher

2017-01-01

Researchers from the University of Michigan (UM) and NASA Goddard Spaceflight Center (GSFC) are partnering to develop new types of magnetometers for use on future small satellites. These new instruments not only fulfill stringent requirements for low-amplitude and high-precision measurements, they are also enabling the team to develop a new approach to achieve high-quality magnetic measurements from space, without the need for a boom. Typically, space-based magnetometers are deployed on a boom that extends from the space vehicle to reduce exposure of magnetic noise emanating from the spacecraft, which could potentially contaminate measurements. The UMNASA team has developed algorithms to identify and eliminate spacecraft magnetic noise, which will allow placement of these economical, science-grade instrument magnetometers on and inside the satellite bus, instead of on a boom.

Field-Programmable Gate Array-based fluxgate magnetometer with digital integration

NASA Astrophysics Data System (ADS)

Butta, Mattia; Janosek, Michal; Ripka, Pavel

2010-05-01

In this paper, a digital magnetometer based on printed circuit board fluxgate is presented. The fluxgate is pulse excited and the signal is extracted by gate integration. We investigate the possibility to perform integration on very narrow gates (typically 500 ns) by using digital techniques. The magnetometer is based on field-programmable gate array (FPGA) card: we will show all the advantages and disadvantages, given by digitalization of fluxgate output voltage by means of analog-to-digital converter on FPGA card, as well as digitalization performed by external digitizer. Due to very narrow gate, it is shown that a magnetometer entirely based on a FPGA card is preferable, because it avoids noise due to trigger instability. Both open loop and feedback operative mode are described and achieved results are presented.

Demonstration of sensitivity increase in mercury free-spin-precession magnetometers due to laser-based readout for neutron electric dipole moment searches

NASA Astrophysics Data System (ADS)

Ban, G.; Bison, G.; Bodek, K.; Daum, M.; Fertl, M.; Franke, B.; Grujić, Z. D.; Heil, W.; Horras, M.; Kasprzak, M.; Kermaidic, Y.; Kirch, K.; Koch, H.-C.; Komposch, S.; Kozela, A.; Krempel, J.; Lauss, B.; Lefort, T.; Mtchedlishvili, A.; Pignol, G.; Piegsa, F. M.; Prashanth, P.; Quéméner, G.; Rawlik, M.; Rebreyend, D.; Ries, D.; Roccia, S.; Rozpedzik, D.; Schmidt-Wellenburg, P.; Severijns, N.; Weis, A.; Wyszynski, G.; Zejma, J.; Zsigmond, G.

2018-07-01

We report on a laser based 199Hg co-magnetometer deployed in an experiment searching for a permanent electric dipole moment of the neutron. We demonstrate a more than five times increased signal to-noise-ratio in a direct comparison measurement with its 204Hg discharge bulb-based predecessor. An improved data model for the extraction of important system parameters such as the degrees of absorption and polarization is derived. Laser- and lamp-based data-sets can be consistently described by the improved model which permits to compare measurements using the two different light sources and to explain the increase in magnetometer performance. The laser-based magnetometer satisfies the magnetic field sensitivity requirements for the next generation nEDM experiments.

Magnetosphere - ionosphere coupling process in the auroral region estimated from auroral tomography

NASA Astrophysics Data System (ADS)

Tanaka, Y.; Ogawa, Y.; Kadokura, A.; Gustavsson, B.; Kauristie, K.; Whiter, D. K.; Enell, C. F. T.; Brandstrom, U.; Sergienko, T.; Partamies, N.; Kozlovsky, A.; Miyaoka, H.; Kosch, M. J.

2016-12-01

We have studied the magnetosphere - ionosphere coupling process by using multiple auroral images and the ionospheric data obtained by a campaign observation with multi-point imagers and the EISCAT UHF radar in Northern Europe. We observed wavy structure of discrete arcs around the magnetic zenith at Tromso, Norway, from 22:00 to 23:15 UT on March 14, 2015, followed by auroral breakup, poleward expansion, and pulsating auroras. During this interval, the monochromatic (427.8nm) images were taken at a sampling interval of 2 seconds by three EMCCD imagers and at an interval of 10 seconds by totally six imagers. The EISCAT UHF radar at Tromso measured the ionospheric parameters along the magnetic field line from 20 to 24 UT. We applied the tomographic inversion technique to these data set to retrieve 3D distribution of the 427.8nm emission, that enabled us to obtain the following quantities for the auroras that change from moment to moment; (1) the relation between the 427.8nm emission and the electron density enhancement along the field line, (2) the horizontal distribution of energy flux of auroral precipitating electrons, and (3) the horizontal distribution of height-integrated ionospheric conductivity. By combining those with the ionospheric equivalent current estimated from the ground-based magnetometer network, we discuss the current system of a sequence of the auroral event in terms of the magnetosphere-ionosphere coupling.

Improved Ionospheric Electrodynamic Models and Application to Calculating Joule Heating Rates

NASA Technical Reports Server (NTRS)

Weimer, D. R.

2004-01-01

Improved techniques have been developed for empirical modeling of the high-latitude electric potentials and magnetic field aligned currents (FAC) as a function of the solar wind parameters. The FAC model is constructed using scalar magnetic Euler potentials, and functions as a twin to the electric potential model. The improved models have more accurate field values as well as more accurate boundary locations. Non-linear saturation effects in the solar wind-magnetosphere coupling are also better reproduced. The models are constructed using a hybrid technique, which has spherical harmonic functions only within a small area at the pole. At lower latitudes the potentials are constructed from multiple Fourier series functions of longitude, at discrete latitudinal steps. It is shown that the two models can be used together in order to calculate the total Poynting flux and Joule heating in the ionosphere. An additional model of the ionospheric conductivity is not required in order to obtain the ionospheric currents and Joule heating, as the conductivity variations as a function of the solar inclination are implicitly contained within the FAC model's data. The models outputs are shown for various input conditions, as well as compared with satellite measurements. The calculations of the total Joule heating are compared with results obtained by the inversion of ground-based magnetometer measurements. Like their predecessors, these empirical models should continue to be a useful research and forecast tools.

Spatial structure and temporal evolution of energetic particle injections in the inner magnetosphere during the 14 July 2013 substorm event

DOE PAGES

Gkioulidou, Matina; Ohtani, S.; Mitchell, D. G.; ...

2015-03-20

Recent results by the Van Allen Probes mission showed that the occurrence of energetic ion injections inside geosynchronous orbit could be very frequent throughout the main phase of a geomagnetic storm. Understanding, therefore, the formation and evolution of energetic particle injections is critical in order to quantify their effect in the inner magnetosphere. We present a case study of a substorm event that occurred during a weak storm (Dst ~ –40 nT) on 14 July 2013. Van Allen Probe B, inside geosynchronous orbit, observed two energetic proton injections within 10 min, with different dipolarization signatures and duration. The first onemore » is a dispersionless, short-timescale injection pulse accompanied by a sharp dipolarization signature, while the second one is a dispersed, longer-timescale injection pulse accompanied by a gradual dipolarization signature. We combined ground magnetometer data from various stations and in situ particle and magnetic field data from multiple satellites in the inner magnetosphere and near-Earth plasma sheet to determine the spatial extent of these injections, their temporal evolution, and their effects in the inner magnetosphere. Our results indicate that there are different spatial and temporal scales at which injections can occur in the inner magnetosphere and depict the necessity of multipoint observations of both particle and magnetic field data in order to determine these scales.« less

Nanosatellite High-Precision Magnetic Missions Enabled by Advances in a Stand-Alone Scalar/Vector Absolute Magnetometer

NASA Astrophysics Data System (ADS)

Hulot, G.; Leger, J. M.; Vigneron, P.; Jager, T.; Bertrand, F.; Coisson, P.; Deram, P.; Boness, A.; Tomasini, L.; Faure, B.

2017-12-01

Satellites of the ESA Swarm mission currently in operation carry a new generation of Absolute Scalar Magnetometers (ASM), which nominally deliver 1 Hz scalar for calibrating the relative flux gate magnetometers that complete the magnetometry payload (together with star cameras, STR, for attitude restitution) and providing extremely accurate scalar measurements of the magnetic field for science investigations. These ASM instruments, however, can also operate in two additional modes, a high-frequency 250 Hz scalar mode and a 1 Hz absolute dual-purpose scalar/vector mode. The 250 Hz scalar mode already allowed the detection of until now very poorly documented extremely low frequency whistler signals produced by lightning in the atmosphere, while the 1 Hz scalar/vector mode has provided data that, combined with attitude restitution from the STR, could be used to produce scientifically relevant core field and lithospheric field models. Both ASM modes have thus now been fully validated for science applications. Efforts towards developing an improved and miniaturized version of this instrument is now well under way with CNES support in the context of the preparation of a 12U nanosatellite mission (NanoMagSat) proposed to be launched to complement the Swarm satellite constellation. This advanced miniaturized ASM could potentially operate in an even more useful mode, simultaneously providing high frequency (possibly beyond 500 Hz) absolute scalar data and self-calibrated 1 Hz vector data, thus providing scientifically valuable data for multiple science applications. In this presentation, we will illustrate the science such an instrument taken on board a nanosatellite could enable, and report on the current status of the NanoMagSat project that intends to take advantage of it.

A high-sensitivity push-pull magnetometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Breschi, E.; Grujić, Z. D.; Knowles, P.

2014-01-13

We describe our approach to atomic magnetometry based on the push-pull optical pumping technique. Cesium vapor is pumped and probed by a resonant laser beam whose circular polarization is modulated synchronously with the spin evolution dynamics induced by a static magnetic field. The magnetometer is operated in a phase-locked loop, and it has an intrinsic sensitivity below 20fT/√(Hz), using a room temperature paraffin-coated cell. We use the magnetometer to monitor magnetic field fluctuations with a sensitivity of 300fT/√(Hz)

Hidden Markov Model as a Framework for Situational Awareness

DTIC Science & Technology

2008-07-01

line of sight unlike the PIR sensor – they complement each other. Magnetic sensor (B-field sensor): We used both Fluxgate and coil magnetometers ...The former has low frequency response while the coil magnetometer provides high frequency response. A total of six sensors: three fluxgate ...Computer is turned off Figure 7: Fluxgate magnetometer output in x-axis 0 50 100 150 200 250 300 350 400 450 2.6 2.8 3 3.2 3.4 3.6 3.8 4 Time (sec

Vector magnetometer design study: Analysis of a triaxial fluxgate sensor design demonstrates that all MAGSAT Vector Magnetometer specifications can be met

NASA Technical Reports Server (NTRS)

Adams, D. F.; Hartmann, U. G.; Lazarow, L. L.; Maloy, J. O.; Mohler, G. W.

1976-01-01

The design of the vector magnetometer selected for analysis is capable of exceeding the required accuracy of 5 gamma per vector field component. The principal elements that assure this performance level are very low power dissipation triaxial feedback coils surrounding ring core flux-gates and temperature control of the critical components of two-loop feedback electronics. An analysis of the calibration problem points to the need for improved test facilities.

The Detection and Discrimination of Small Munitions using Giant Magnetoresistive (OMR) Sensors

DTIC Science & Technology

2010-09-01

Suffield, Canada. McGlone, D.T., 1998, Magnetometer Comparison Smoke Creek Instruments’ GMR SCIMAG- 01 & Bartington Fluxgate MAG-03MC70, A...a magnetometer and frequency domain or time domain electromagnetic induction sensor. Both the Honeywell and NVE GlvlR sensors studied have si.m ilar...field sensor. In p0ssive mode, the GMR sensor, which has a resolution of Jess than l 0 nT, perfom1ed similarly to a cesium vapor magnetometer . When

On-Time 3D Time-Domain EMI and Tensor Magnetic Gradiometry for UXO Detection and Discrimination

DTIC Science & Technology

2008-06-04

three-axis fluxgate magnetometers mounted on a tetrahedral structure as shown in figure 5.1.3.1. TMGS was intended to measure gradients of vector...manufacturer of the fluxgate magnetometers supplied specifications for each of the triaxial sensors (figure 5.3.2.25). Figure 5.3.2.25...Manufacturer’s specifications for the four triaxial fluxgate magnetometers used in the TMGS planar array. As shown previously in figure 5.3.2.4

Spacecraft Instrumentation to Measure and Stimulate Space Particles and Plasma Waves in the Medium-Earth Orbit (MEO) Regime

DTIC Science & Technology

2006-07-12

fluxgate magnetometer for the AFRL-DSX mission. The instrument is designed to measure the medium-Earth orbit geomagnetic field with precision of 0.1 nT and...which is essential to fulfill the two primary goals of the DSX science program. 1.1. Scientific Rationale: Ring Current and The fluxgate magnetometer ...UCLA’s ments and the Radiation Belt Remediation primary motivation in providing fluxgate requirements. The magnetic field is necessary magnetometers for

Proceedings of the Air Force Geophysics Laboratory Workshop on the Earth’s Radiation Belts: 26-27 January 1981.

DTIC Science & Technology

1981-10-21

characteristics of five types of magnetometers flown on spacecraft. These are: (1) search coils, (2) fluxgates , (3)proton precession, (4) alkali vapor and... Fluxgate magnetometers are most useful for measuring the dc magnetic field of the earth as well as its low frequency (:s 100 Hz) fluctuations...Characteristics of fluxgates are discussed in detail in the paragraphs immediately following. The last three types of magnetometers provide very high resolution

Geomagnetic field observations at a new Antarctic site, within the AIMNet project

NASA Astrophysics Data System (ADS)

Lepidi, Stefania; Cafarella, Lili; Santarelli, Lucia; Pietrolungo, Manuela; Urbini, Stefano; Piancatelli, Andrea; Biasini, Fulvio; di Persio, Manuele; Rose, Mike

2010-05-01

During the 2007-2008 antarctic campaign, the Italian PNRA installed a Low Power Magnetometer within the framework of the AIMNet (Antarctic International Magnetometer Network) project, proposed and coordinated by BAS. The magnetometer is situated at Talos Dome, around 300 km geographically North-West from Mario Zucchelli Station (MZS), and approximately at the same geomagnetic latitude as MZS. In this work we present a preliminary analysis of the geomagnetic field 1-min data, and a comparison with simultaneous data from different Antarctic stations.

Estimating Antarctic Near-Surface Magnetic Anomalies from Oersted and CHAMP Satellite Magnetometer Observations

NASA Technical Reports Server (NTRS)

vonFrese, Ralph R. B.; Kim, Hyung Rae; Gaya-Pique, Luis R.; Taylor, Patrick T.; Golynsky, Alexander V.; Kim, Jeong Woo

2004-01-01

Significant improvement in predicting near-surface magnetic anomalies can result from the highly accurate magnetic observations of the CHAMP satellite that is orbiting at about 400 km altitude. In general, regional magnetic signals of the crust are strongly masked by the core field and its secular variations due to wavelength coupling in the spherical harmonic representation and thus are difficult to isolate in the satellite measurements. However, efforts to isolate the regional lithospheric from core field components can exploit the correlations between the CHAMP magnetic anomalies and the pseudo magnetic effects inferred from gravity-derived crustal thickness variations. In addition, we can use spectral correlation theory to filter the static lithospheric field components from the dynamic external field effects. Employing these procedures, we processed the CHAMP magnetic conservations for an improved magnetic anomaly map of the Antarctic crust. Relative to the much higher altitude Oersted and noisier Magsat observations, CHAMP magnetic anomalies at 400 km altitude reveal new details on the effects of intra-crustal magnetic features and crustal thickness variations of the Antarctic. Moreover, these results greatly facilitate predicting magnetic anomalies in the regional coverage gaps of the ADMAP compilation of Antarctic magnetic anomalies from shipborne, airborne and ground surveys. Our analysis suggests that considerable new insights on the magnetic properties of the lithosphere may be revealed by a further order-of-magnitude improvement in the accuracy of the magnetometer.

Thermosphere-Ionosphere Fe/Fe+ (TIFe) Layers and Their Coupling with Geomagnetic Storms and Solar Wind

NASA Astrophysics Data System (ADS)

Chu, X.; Xu, Z.; Zhao, J.; Yu, Z.; Knipp, D. J.; Kilcommons, L. M.; Chen, C.; Fong, W.; Barry, I. F.; Hartinger, M.

2016-12-01

The discovery of thermospheric neutral Fe layers by lidar observations in Antarctica has opened a new door to explore the space-atmosphere interactions with ground-based instruments, especially in the least understood but crucially important altitude range of 100-200 km. These neutral metal layers provide excellent tracers for modern resonance lidars to measure the neutral wind and temperature directly, complementing the radar measurements of the ionosphere and the magnetometer measurements of the geomagnetic field. Even more exciting, the neutral metal layers in the thermosphere provide a natural laboratory to test our fundamental understandings of the atmosphere-ionosphere-magnetosphere (AIM) coupling and processes. The stunning Fe layer event on 28 May 2011 with clear gravity wave signatures has been simulated successfully with the University of Colorado Thermosphere-Ionosphere Fe/Fe+ (TIFe) model, confirming the theoretical hypothesis that such thermospheric Fe layers are produced through the neutralization of converged Fe+layers. Over 5.5 years of lidar observations at McMurdo have revealed many more cases with variety of patterns - besides the `gravity wave' patterns, there are `diffusive' patterns with both upward and downward phase progressions of Fe layers, and `superposition' patterns with both gravity wave signature and diffusive background. Surprisingly, these Fe layer events exhibit close correlations with geomagnetic storms. They also correspond to remarkable activity of extreme solar wind events, e.g., high-speed stream (HSS) and coronal mass ejection (CME), etc. This paper conducts a systematic investigation of the coupling among TIFe layers, geomagnetic storms, solar wind and IMF via combining ground-based lidar, magnetometer, and SuperDARN data with DMSP, ACE and WIND satellite data along with the TIFe model simulations. We aim to quantitatively determine the relationship between TIFe and magnetic storms, and explore the mechanisms responsible for such correlations. The new insights gained through this investigation will certainly advance our understandings of the AIM coupling processes, especially the neutral atmosphere responses to geomagnetic storms and solar activity.

Comparison of a triaxial fluxgate magnetometer and Toftness sensometer for body surface EMF measurement.

PubMed

Zhang, John; Toftness, Dave; Snyder, Brian; Nosco, Dennis; Balcavage, Walter; Nindl, Gabi

2004-12-01

The use of magnetic fields to treat disease has intrigued mankind since the time of the ancient Greeks. More recently it has been shown that electromagnetic field (EMF) treatment aids bone healing, and repetitive transcranial magnetic stimulation (rTMS) appears to be beneficial in treating schizophrenia and depression. Since external EMFs influence internal body processes, we hypothesized that measurement of body surface EMFs might be used to detect disease states and direct the course of subsequent therapy. However, measurement of minute body surface EMFs requires use of a sensitive and well documented magnetometer. In this study we evaluated the sensitivity and frequency response of a fluxgate magnetometer with a triaxial probe for use in detecting body surface EMF and we compared the magnetometer readings with a signal from a Toftness Sensometer, operated by an experienced clinician, in the laboratory and in a clinical setting. A Peavy Audio Amplifier and variable power output Telulex signal generator were used to develop 50 microT EMFs in a three coil Merritt coil system. A calibrated magnetometer was used to set a 60 Hz 50 microT field in the coil and an ammeter was used to measure the current required to develop the 50 microT field. At frequencies other than 60 Hz, the field strength was maintained at 50 microT by adjusting the Telulex signal output to keep the current constant. The field generated was monitored using a 10 turn coil connected to an oscilloscope. The oscilloscope reading indicated that the field strength was the same at all frequencies tested. To determine if there was a correspondence between the signals detected by a fluxgate magnetometer (FGM1) and the Toftness Sensometer both devices were placed in the Merritt coil and readings were recorded from the FGM1 and compared with the ability of a highly experienced Toftness operator to detect the 50 microT field. Subsequently, in a clinical setting, FGM1 readings made by an FGM1 technician and Sensometer readings were made by 4 Toftness Sensometer operators, having various degrees of experience with this device. Each examiner obtained instrument readings from 5 different volunteers in separate chiropractic adjusting rooms. Additionally, one of the Toftness Sensometers was equipped with an integrated fluxgate magnetometer (FGM2) and this magnetometer was used to obtain a second set of EMF readings in the clinical setting. The triaxial fluxgate magnetometer was determined to be moderately responsive to changes in magnetic field frequency below 10 Hz. At frequencies above 10 Hz the readings corresponded to that of the ambient static geofield. The practitioner operating the Toftness Sensometer was unable to detect magnetic fields at high frequencies (above 10 Hz) even at very high EMFs. The fluxgate magnetometer was shown to be essentially a DC/static magnetic field detector and like all such devices it has a limited frequency range with some low level of sensitivity at very low field frequencies. The interexaminer reliability of four Toftness practitioners using the Sensometer on 5 patients showed low to moderate correlation. The fluxgate magnetometer although highly sensitive to static (DC) EMFs has only limited sensitivity to EMFs in the range of 1 to 10 Hz and is very insensitive to frequencies above 10 Hz. In laboratory comparisons of the Sensometer and the fluxgate magnetometer there was an occasional correspondence between the two instruments in detecting magnetic fields within the Merritt coil but these occasions were not reproducible. In the clinical studies there was low to moderate agreement between the clinicians using the Sensometer to diagnosing spinal conditions and there was little if any agreement between the Sensometer and the fluxgate magnetometer in detecting EMFs emanating from the volunteers body surface.

Comparison of a triaxial fluxgate magnetometer and Toftness sensometer for body surface EMF measurement

PubMed Central

Zhang, John; Toftness, Dave; Snyder, Brian; Nosco, Dennis; Balcavage, Walter; Nindl, Gabi

2004-01-01

Introduction The use of magnetic fields to treat disease has intrigued mankind since the time of the ancient Greeks. More recently it has been shown that electromagnetic field (EMF) treatment aids bone healing, and repetitive transcranial magnetic stimulation (rTMS) appears to be beneficial in treating schizophrenia and depression. Since external EMFs influence internal body processes, we hypothesized that measurement of body surface EMFs might be used to detect disease states and direct the course of subsequent therapy. However, measurement of minute body surface EMFs requires use of a sensitive and well documented magnetometer. In this study we evaluated the sensitivity and frequency response of a fluxgate magnetometer with a triaxial probe for use in detecting body surface EMF and we compared the magnetometer readings with a signal from a Toftness Sensometer, operated by an experienced clinician, in the laboratory and in a clinical setting. Methods A Peavy Audio Amplifier and variable power output Telulex signal generator were used to develop 50 μT EMFs in a three coil Merritt coil system. A calibrated magnetometer was used to set a 60 Hz 50 μT field in the coil and an ammeter was used to measure the current required to develop the 50 μT field. At frequencies other than 60 Hz, the field strength was maintained at 50 μT by adjusting the Telulex signal output to keep the current constant. The field generated was monitored using a 10 turn coil connected to an oscilloscope. The oscilloscope reading indicated that the field strength was the same at all frequencies tested. To determine if there was a correspondence between the signals detected by a fluxgate magnetometer (FGM1) and the Toftness Sensometer both devices were placed in the Merritt coil and readings were recorded from the FGM1 and compared with the ability of a highly experienced Toftness operator to detect the 50 μT field. Subsequently, in a clinical setting, FGM1 readings made by an FGM1 technician and Sensometer readings were made by 4 Toftness Sensometer operators, having various degrees of experience with this device. Each examiner obtained instrument readings from 5 different volunteers in separate chiropractic adjusting rooms. Additionally, one of the Toftness Sensometers was equipped with an integrated fluxgate magnetometer (FGM2) and this magnetometer was used to obtain a second set of EMF readings in the clinical setting. Results The triaxial fluxgate magnetometer was determined to be moderately responsive to changes in magnetic field frequency below 10 Hz. At frequencies above 10 Hz the readings corresponded to that of the ambient static geofield. The practitioner operating the Toftness Sensometer was unable to detect magnetic fields at high frequencies (above 10 Hz) even at very high EMFs. The fluxgate magnetometer was shown to be essentially a DC/static magnetic field detector and like all such devices it has a limited frequency range with some low level of sensitivity at very low field frequencies. The interexaminer reliability of four Toftness practitioners using the Sensometer on 5 patients showed low to moderate correlation. Conclusions The fluxgate magnetometer although highly sensitive to static (DC) EMFs has only limited sensitivity to EMFs in the range of 1 to 10 Hz and is very insensitive to frequencies above 10 Hz. In laboratory comparisons of the Sensometer and the fluxgate magnetometer there was an occasional correspondence between the two instruments in detecting magnetic fields within the Merritt coil but these occasions were not reproducible. In the clinical studies there was low to moderate agreement between the clinicians using the Sensometer to diagnosing spinal conditions and there was little if any agreement between the Sensometer and the fluxgate magnetometer in detecting EMFs emanating from the volunteers body surface. PMID:17549105

The Noise Level Optimization for Induction Magnetometer of SEP System

NASA Astrophysics Data System (ADS)

Zhu, W.; Fang, G.

2011-12-01

The Surface Electromagnetic Penetration (SEP) System, subsidized by the SinoProbe Plan in China, is designed for 3D conductivity imaging in geophysical mineral exploration, underground water distribution exploration, oil and gas reservoir exploration. Both the Controlled Source Audio Magnetotellurics (CSAMT) method and Magnetotellurics (MT) method can be surveyed by SEP system. In this article, an optimization design is introduced, which can minimize the noise level of the induction magnetometer for SEP system magnetic field's acquisition. The induction magnetometer transfers the rate of the magnetic field's change to voltage signal by induction coil, and amplified it by Low Noise Amplifier The noise parts contributed to the magnetometer are: the coil's thermal noise, the equivalent input voltage and current noise of the pre-amplifier. The coil's thermal noise is decided by coil's DC resistance. The equivalent input voltage and current noise of the pre-amplifier depend on the amplifier's type and DC operation condition. The design here optimized the DC operation point of pre-amplifier, adjusted the DC current source, and realized the minimum of total noise level of magnetometer. The calculation and test results show that: the total noise is about 1pT/√Hz, the thermal noise of coils is 1.7nV/√Hz, the preamplifier equivalent input voltage and current noise is 3nV/ √Hz and 0.1pA/√Hz, the weight of the magnetometer is 4.5kg and meet the requirement of SEP system.

Design and implementation of JOM-3 Overhauser magnetometer analog circuit

NASA Astrophysics Data System (ADS)

Zhang, Xiao; Jiang, Xue; Zhao, Jianchang; Zhang, Shuang; Guo, Xin; Zhou, Tingting

2017-09-01

Overhauser magnetometer, a kind of static-magnetic measurement system based on the Overhauser effect, has been widely used in archaeological exploration, mineral resources exploration, oil and gas basin structure detection, prediction of engineering exploration environment, earthquakes and volcanic eruotions, object magnetic measurement and underground buried booty exploration. Overhauser magnetometer plays an important role in the application of magnetic field measurement for its characteristics of small size, low power consumption and high sensitivity. This paper researches the design and the application of the analog circuit of JOM-3 Overhauser magnetometer. First, the Larmor signal output by the probe is very weak. In order to obtain the signal with high signal to noise rstio(SNR), the design of pre-amplifier circuit is the key to improve the quality of the system signal. Second, in this paper, the effectual step which could improve the frequency characters of bandpass filter amplifier circuit were put forward, and theoretical analysis was made for it. Third, the shaping circuit shapes the amplified sine signal into a square wave signal which is suitable for detecting the rising edge. Fourth, this design elaborated the optimized choice of tuning circuit, so the measurement range of the magnetic field can be covered. Last, integrated analog circuit testing system was formed to detect waveform of each module. By calculating the standard deviation, the sensitivity of the improved Overhauser magnetometer is 0.047nT for Earth's magnetic field observation. Experimental results show that the new magnetometer is sensitive to earth field measurement.

Vector magnetometer based on synchronous manipulation of nitrogen-vacancy centers in all crystal directions

NASA Astrophysics Data System (ADS)

Zhang, Chen; Yuan, Heng; Zhang, Ning; Xu, Lixia; Zhang, Jixing; Li, Bo; Fang, Jiancheng

2018-04-01

Negatively charged nitrogen vacancy (NV‑) centers in diamond have been extensively studied as high-sensitivity magnetometers, showcasing a wide range of applications. This study experimentally demonstrates a vector magnetometry scheme based on synchronous manipulation of NV‑ center ensembles in all crystal directions using double frequency microwaves (MWs) and multi-coupled-strip-lines (mCSL) waveguide. The application of the mCSL waveguide ensures a high degree of synchrony (99%) for manipulating NV‑ centers in multiple orientations in a large volume. Manipulation with double frequency MWs makes NV‑ centers of all four crystal directions involved, and additionally leads to an enhancement of the manipulation field. In this work, by monitoring the changes in the slope of the resonance line consisting of multi-axes NV‑ centers, measurement of the direction of the external field vector was demonstrated with a sensitivity of {{10}\\prime}/\\sqrt{Hz} . Based on the scheme, the fluorescence signal contrast was improved by four times higher and the sensitivity to the magnetic field strength was improved by two times. The method provides a more practical way of achieving vector sensors based on NV‑ center ensembles in diamond.

The magnetic field of gastrointestinal smooth muscle activity

NASA Astrophysics Data System (ADS)

Bradshaw, Alan; Ladipo, Jk; Richards, William; Wikswo, John

1997-11-01

The gastrointestinal (GI) tract controls the absorption and transport of ingested materials. Its function is determined largely by the electrical activity of the smooth muscle that lines the GI tract. GI electrical activity consists of an omnipresent slowly oscillating wave known as the basic electrical rhythm (BER) that modulates a higher-frequency spiking activity associated with muscle contraction. The BER has been shown to be a reliable indicator of intestinal viability, and thus, recording of smooth muscle activity may have clinical value. The BER is difficult to measure with cutaneous electrodes because layers of low-conductivity fat between the GI tract and the abdominal surface attenuate the potential. On the other hand, the magnetic field associated with GI electrical activity is mostly unaffected by intervening fat layers. We recorded the magnetic fields from GI activity in 12 volunteers using a multichannel Superconducting QUantum Interference Device (SQUID) magnetometer. Characteristics typical of gastric and intestinal BER were apparent in the data. Channels near the epigastrium recorded gastric BER, and channels in intestinal areas recorded small bowel BER. These results suggest that a single multichannel SQUID magnetometer is able to measure gastrointestinal electrical activity from multiple locations around the abdomen simultaneously.

The Transition Region Explorer: Observing the Multi-Scale Dynamics of Geospace

NASA Astrophysics Data System (ADS)

Donovan, E.

2015-12-01

Meso- and global-scale IT remote sensing is accomplished via satellite imagers and ground-based instruments. On the ground, the approach is arrays providing extensive as possible coverage (the "net") and powerful observatories that drill deep to provide detailed information about small-scale processes (the "drill"). Always, there is a trade between cost, spatial resolution, coverage (extent), number of parameters, and more, such that in general the larger the network the sparser the coverage. Where are we now? There are important gaps. With THEMIS-ASI, we see processes that quickly evolve beyond the field of view of one observatory, but involve space/time scales not captured by existing meso- and large-scale arrays. Many forefront questions require observations at heretofore unexplored space and time scales, and comprehensive inter-hemispheric conjugate observations than are presently available. To address this, a new ground-based observing initiative is being developed in Canada. Called TREx, for Transition Region Explorer, this new facility will incorporate dedicated blueline, redline, and Near-Infrared All-Sky Imagers, together with an unprecedented network of ten imaging riometers, with a combined field of view spanning more than three hours of magnetic local time and from equatorward to poleward of typical auroral latitudes (spanning the ionospheric footprint of the "nightside transition region" that separates the highly stretched tail and the inner magnetosphere). The TREx field-of-view is covered by HF radars, and contains a dense network of magnetometers and VLF receivers, as well as other geospace and upper atmospheric remote sensors. Taken together, TREx and these co-located instruments represent a quantum leap forward in terms of imaging, in multiple parameters (precipitation, ionization, convection, and currents), ionospheric dynamics in the above-mentioned scale gap. This represents an exciting new opportunity for studying geospace at the system level, especially for using the aurora to remote sense magnetospheric plasma physics and dynamics, and comes with a set of Big Data challenges that are going to be exciting. One such challenge is the development of a fundamentally new type of data product, namely time series of multi-parameter, geospatially referenced 'data cubes'.

Magnetometry and archaeological prospection in Mexico

NASA Astrophysics Data System (ADS)

Barba Pingarron, L.; Laboratorio de Prospeccion Arqueologica

2013-05-01

Luis Barba Laboratorio de Prospección Arqueológica Instituto de Investigaciones Antropológicas Universidad Nacional Autonoma de México The first magnetic survey in archaeological prospection was published in 1958 in the first number of Archaeometry, in Oxford. That article marked the beginning of this applications to archaeology. After that, magnetic field measurements have become one of the most important and popular prospection tools. Its most outstanding characteristic is the speed of survey that allows to cover large areas in short time. As a consequence, it is usually the first approach to study a buried archaeological site. The first attempts in Mexico were carried out in 196. Castillo and Urrutia, among other geophysical techniques, used a magnetometer to study the northern part of the main plaza, zocalo, in Mexico City to locate some stone Aztec sculptures. About the same time Morrison et al. in La Venta pyramid used a magnetometer to measure total magnetic field trying to find a substructure. Some years later Brainer and Coe made a magnetic survey to locate large stone Olmec heads in San Lorenzo Tenochtitlan, Veracruz. Technology development has provided everyday more portable and accurate instruments to measure the magnetic field. The first total magnetic field proton magnetometers were followed by differential magnetometers and more recently gradiometers. Presently, multiple sensor magnetometers are widely used in European archaeology. The trend has been to remove the environmental and modern interference and to make more sensitive the instruments to the superficial anomalies related to most of the archaeological sites. There is a close relationship between the geology of the region and the way magnetometry works in archaeological sites. Archaeological prospection in Europe usually needs very sensitive instruments to detect slight magnetic contrast of ditches in old sediments. In contrast, volcanic conditions in Mexico produce large magnetic contrast between the igneous rocks and the sediments in archaeological context, thus the use of less sensitive instruments works fine for these conditions. Surveys in archaeological sites in Mexico during last 30 years have provided enough evidence that the best conditions to apply magnetic prospection is in lacustrine environment where the ancient inhabitants used igneous rocks as building material. These conditions has been more common than expected in the Trans volcanic Belt where most of the lakes were densely occupied in ancient times. Because most lakes were surrounded by quite recent volcanos, it was pretty common to use the basaltic and andesitic rocks to build the archaeological structures. In this contribution some of the most successful applications of the magnetic technique in archaeology will be shown to illustrate the possibilities of the magnetometry in archaeological prospection.

Validation of the GOES-16 magnetometer using multipoint measurements and magnetic field models

NASA Astrophysics Data System (ADS)

Califf, S.; Loto'aniu, P. T. M.; Redmon, R. J.; Sarris, T. E.; Brito, T.

2017-12-01

The Geostationary Operational Environmental Satellites (GOES) have been providing continuous geomagnetic field measurements for over 40 years. While the primary purpose of GOES is operational, the magnetometer data are also widely used in the scientific community. In an effort to validate the recently launched GOES-16 magnetometer, we compare the measurements to existing magnetic field models and other GOES spacecraft currently on orbit. There are four concurrent measurements from GOES-13, 14, 15 and 16 spanning 75W to 135W longitude. Also, GOES-13 is being replaced by GOES-16 in the GOES-East location, and during the transition, GOES-13 and GOES-16 will be parked nearby in order to assist with calibration of the new operational satellite. This work explores techniques to quantify the performance of the GOES-16 magnetometer by comparison to data from nearby spacecraft. We also build on previous work to assimilate in situ measurements with existing magnetic field models to assist in comparing data from different spatial locations. Finally, we use this unique dataset from four simultaneous geosynchronous magnetometer measurements and the close separation between GOES-13 and GOES-16 to study the spatial characteristics of ULF waves and other magnetospheric processes.

THOR Fluxgate Magnetometer (MAG)

NASA Astrophysics Data System (ADS)

Nakamura, Rumi; Eastwood, Jonathan; Magnes, Werner; Valavanoglou, Aris; Carr, Christopher M.; O'Brien, Helen L.; Narita, Yasuhito; Delva, Magda; Chen, Christopher H. K.; Plaschke, Ferdinand; Soucek, Jan

2016-04-01

Turbulence Heating ObserveR (THOR) is the first mission ever flown in space dedicated to plasma turbulence. The goal of the Fluxgate Magnetometer (MAG) is to measure the DC to low frequency ambient magnetic field. The design of the magnetometer consists of two tri-axial sensors and the related magnetometer electronics; the electronics are hosted on printed circuit boards in the common electronics box of the fields and wave processor (FWP). A fully redundant two sensor system mounted on a common boom and the new miniaturized low noise design based on MMS and Solar Orbiter instruments enable accurate measurement throughout the region of interest for THOR science. The usage of the common electronics hosted by FWP guarantees to fulfill the required timing accuracy with other fields measurements. These improvements are important to obtain precise measurements of magnetic field, which is essential to estimate basic plasma parameters and correctly identify the spatial and temporal scales of the turbulence. Furthermore, THOR MAG provides high quality data with sufficient overlap with the Search Coil Magnetometer (SCM) in frequency space to obtain full coverage of the wave forms over all the frequencies necessary to obtain the full solar wind turbulence spectrum from MHD to kinetic range with sufficient accuracy.

Induction magnetometer using a high-Tc superconductor coil

NASA Astrophysics Data System (ADS)

Sasada, Ichiro

2010-05-01

An induction magnetometer consisting of a search coil and an inverting operational amplifier is simple in structure and in signal transferring mechanism from the magnetic field input to the voltage output. Because this magnetometer is based on Faraday's law of induction, it has a lower cutoff frequency r/(2πL), where r is the resistance of the coil and L is its inductance. An attempt has been made to lower the cutoff frequency of the induction magnetometer by using a high-Tc superconductor coil. With a pancake coil (inner diameter ≈18 cm and outer diameter ≈23 cm, 92 turns, 3.23 mH) made of a Bismuth strontium calcium copper oxide (BSCCO) superconductor tape of 5 mm in width and 0.23 mm in thickness, the cutoff frequency achieved was 1.7 Hz which is much lower than that obtained with a bulky copper search coil which is typically in the range of 10-20 Hz. In the experiment, an inverting amplifier was made with a complementary metal-oxide semiconductor operational amplifier and was immersed in liquid nitrogen together with a BSCCO high-Tc superconducting coil. Discussion is made on the resolution of the induction magnetometer using a high-Tc superconductor search coil.

Construction and calibration of a low cost and fully automated vibrating sample magnetometer

NASA Astrophysics Data System (ADS)

El-Alaily, T. M.; El-Nimr, M. K.; Saafan, S. A.; Kamel, M. M.; Meaz, T. M.; Assar, S. T.

2015-07-01

A low cost vibrating sample magnetometer (VSM) has been constructed by using an electromagnet and an audio loud speaker; where both are controlled by a data acquisition device. The constructed VSM records the magnetic hysteresis loop up to 8.3 KG at room temperature. The apparatus has been calibrated and tested by using magnetic hysteresis data of some ferrite samples measured by two scientifically calibrated magnetometers; model (Lake Shore 7410) and model (LDJ Electronics Inc. Troy, MI). Our VSM lab-built new design proved success and reliability.

Aircraft attitude measurement using a vector magnetometer

NASA Technical Reports Server (NTRS)

Peitila, R.; Dunn, W. R., Jr.

1977-01-01

The feasibility of a vector magnetometer system was investigated by developing a technique to determine attitude given magnetic field components. Sample calculations are then made using the earth's magnetic field data acquired during actual flight conditions. Results of these calculations are compared graphically with measured attitude data acquired simultaneously with the magnetic data. The role and possible implementation of various reference angles are discussed along with other pertinent considerations. Finally, it is concluded that the earth's magnetic field as measured by modern vector magnetometers can play a significant role in attitude control systems.

Development and Evaluation of an Airborne Superconducting Quantum Interference Device-Based Magnetic Gradiometer Tensor System for Detection, Characterization and Mapping of Unexploded Ordnance

DTIC Science & Technology

2008-08-01

Figure 17: USGS Helmholtz coils with SQUID and fluxgate magnetometers installed. 22 Figure 18: Plot of SQUID and fluxgate data from a rotating... fluxgate magnetometer , each sensor measures flux in only one direction. Combinations of SQUID sensor elements are arranged in various configurations...than the absolute field value the way that a fluxgate magnetometer would do. If the SQUID is shut down or loses lock, it has no way to relate the new

A Study of the Association of Pc 3, 4 Micropulsations with Interplanetary Magnetic Field Orientation & Other Solar Wind Parameters.

DTIC Science & Technology

1977-11-13

Page 13 DEPENDENCE OF MEDIAN LOG POWER 1.0 ON SOLAR WIND VELOCITY Pc3 PULSATIONS June - September 1974 UCLA Fluxgate Magnetometer ATS - 6 0 Log P=-3.3...interplanetary medium; Cosmic Elec., 1, 90-114, Space Sci. Rev., in press, 1978. 1970. Rusaell, C T., The ISEE I and 2 fluxgate magnetometers IEEE Fairfield. D...investigation is to attain the capacity to use micropulsation records acquired from surface magnetometers to infer certain key parameters of the solar wind

Calibration of Helmholtz Coils for the characterization of MEMS magnetic sensor using fluxgate magnetometer with DAS1 magnetic range data acquisition system

NASA Astrophysics Data System (ADS)

Ahmad, Farooq; Dennis, John Ojur; Md Khir, Mohd Haris; Hamid, Nor Hisham

2012-09-01

This paper presents the calibration of Helmholtz coils for the characterization of MEMS Magnetic sensor using Fluxgate magnetometer with DAS1 Magnetic Range Data Acquisition System. The Helmholtz coils arrangement is often used to generate a uniform magnetic field in space. In the past, standard magnets were used to calibrate the Helmholtz coils. A method is presented here for calibrating these coils using a Fluxgate magnetometer and known current source, which is easier and results in greater accuracy.

Measuring the magnetic fields of Jupiter and the outer solar system

NASA Technical Reports Server (NTRS)

Smith, E. J.; Connor, B. V.; Foster, G. T., Jr.

1975-01-01

The vector helium magnetometer, one of the Pioneer-Jupiter experiments, has measured the magnetic field of Jupiter and the interplanetary magnetic field in the outer solar system. The comprehensive scientific objectives of the investigations are explained and are then translated into the major instrument requirements. The principles of operation of the magnetometer, which involve the optical pumping of metastable helium, are discussed and the Pioneer instrument is described. The in-flight performance of the magnetometer is discussed and principal scientific results obtained thus far by the Pioneer investigation are summarized.

Microfabricated optically pumped magnetometer arrays for biomedical imaging

NASA Astrophysics Data System (ADS)

Perry, A. R.; Sheng, D.; Krzyzewski, S. P.; Geller, S.; Knappe, S.

2017-02-01

Optically-pumped magnetometers have demonstrated magnetic field measurements as precise as the best superconducting quantum interference device magnetometers. Our group develops miniature alkali atom-based magnetic sensors using microfabrication technology. Our sensors do not require cryogenic cooling, and can be positioned very close to the sample, making these sensors an attractive option for development in the medical community. We will present our latest chip-scale optically-pumped gradiometer developed for array applications to image magnetic fields from the brain noninvasively. These developments should lead to improved spatial resolution, and potentially sensitive measurements in unshielded environments.

Membrane-based torque magnetometer: Enhanced sensitivity by optical readout of the membrane displacement

NASA Astrophysics Data System (ADS)

Blankenhorn, M.; Heintze, E.; Slota, M.; van Slageren, J.; Moores, B. A.; Degen, C. L.; Bogani, L.; Dressel, M.

2017-09-01

The design and realization of a torque magnetometer is reported that reads the deflection of a membrane by optical interferometry. The compact instrument allows for low-temperature measurements of tiny crystals less than a microgram with a significant improvement in sensitivity, signal-to-noise ratio as well as data acquisition time compared with conventional magnetometry and offers an enormous potential for further improvements and future applications in different fields. Magnetic measurements on single-molecule magnets demonstrate the applicability of the membrane-based torque magnetometer.

Membrane-based torque magnetometer: Enhanced sensitivity by optical readout of the membrane displacement.

PubMed

Blankenhorn, M; Heintze, E; Slota, M; van Slageren, J; Moores, B A; Degen, C L; Bogani, L; Dressel, M

2017-09-01

The design and realization of a torque magnetometer is reported that reads the deflection of a membrane by optical interferometry. The compact instrument allows for low-temperature measurements of tiny crystals less than a microgram with a significant improvement in sensitivity, signal-to-noise ratio as well as data acquisition time compared with conventional magnetometry and offers an enormous potential for further improvements and future applications in different fields. Magnetic measurements on single-molecule magnets demonstrate the applicability of the membrane-based torque magnetometer.

Frequency domain and full waveform time domain inversion of ground based magnetometer, electrometer and incoherent scattering radar arrays to image strongly heterogenous 3-D Earth structure, ionospheric structure, and to predict the intensity of GICs in the power grid

NASA Astrophysics Data System (ADS)

Schultz, A.; Imamura, N.; Bonner, L. R., IV; Cosgrove, R. B.

2016-12-01

Ground-based magnetometer and electrometer arrays provide the means to probe the structure of the Earth's interior, the interactions of space weather with the ionosphere, and to anticipate the intensity of geomagnetically induced currents (GICs) in power grids. We present a local-to-continental scale view of a heterogeneous 3-D crust and mantle as determined from magnetotelluric (MT) observations across arrays of ground-based electric and magnetic field sensors. MT impedance tensors describe the relationship between electric and magnetic fields at a given site, thus implicitly they contain all known information on the 3-D electrical resistivity structure beneath and surrounding that site. By using multivariate transfer functions to project real-time magnetic observatory network data to areas surrounding electric power grids, and by projecting those magnetic fields through MT impedance tensors, the projected magnetic field can be transformed into predictions of electric fields along the path of the transmission lines, an essential element of predicting the intensity of GICs in the grid. Finally, we explore GICs, i.e. Earth-ionosphere coupling directly in the time-domain. We consider the fully coupled EM system, where we allow for a non-stationary ionospheric source field of arbitrary complexity above a 3-D Earth. We solve the simultaneous inverse problem for 3-D Earth conductivity and source field structure directly in the time domain. In the present work, we apply this method to magnetotelluric data obtained from a synchronously operating array of 25 MT stations that collected continuous MT waveform data in the interior of Alaska during the autumn and winter of 2015 under the footprint of the Poker Flat (Alaska) Incoherent Scattering Radar (PFISR). PFISR data yield functionals of the ionospheric electric field and ionospheric conductivity that constrain the MT source field. We show that in this region conventional robust MT processing methods struggle to produce reliable MT response functions at periods much greater than about 2,000 s, a consequence, we believe, of the complexity of the ionospheric source fields in this high latitude setting. This provides impetus for direct waveform inversion methods that dispense with typical parametric assumptions made about the MT source fields.

Multi-instrument observations of pre-earthquake transient signatures associated with 2015 M8.3 Chile earthquake

NASA Astrophysics Data System (ADS)

Ouzounov, D.; Pulinets, S. A.; Hernandez-Pajares, M.; Garcia-Rigo, A.; De Santis, A.; Pavón, J.; Liu, J. Y. G.; Chen, C. H.; Cheng, K. C.; Hattori, K.; Stepanova, M. V.; Romanova, N.; Hatzopoulos, N.; Kafatos, M.

2016-12-01

We are conducting multi parameter validation study on lithosphere/atmosphere /ionosphere transient phenomena preceding major earthquakes particularly for the case of M8.3 of Sept 16th, 2015 in Chile. Our approach is based on monitoring simultaneously a series of different physical parameters from space: 1/Outgoing long-wavelength radiation (OLR obtained from NOAA/AVHRR); 2/ electron and electron density variations in the ionosphere via GPS Total Electron Content (GPS/TEC), and 3/geomagnetic field and plasma density variation (Swarm); and from ground: 3/ GPS crustal deformation and 4/ground-based magnetometers. The time and location of main shock was prospectively alerted in advance using the Multi Sensor Networking Approach (MSNA-LAIC) approach. We analyzed retrospectively several physical observations characterizing the state of the lithosphere, atmosphere and ionosphere several days before, during and after the M8.3 earthquakes in Illapel. Our continuous satellite monitoring of long-wave (LW) data over Chile, shows a rapid increase of emitted radiation during the end of August 2015 and an anomaly in the atmosphere was detected at 19 LT on Sept 1st, 2015, over the water near to the epicenter. On Sept 2nd Swarm magnetic measurements show an anomalous signature over the epicentral region. GPS/TEC analysis revealed an anomaly on Sept 14th and on the same day the degradation of Equatorial Ionospheric Anomaly (EIA) and disappearance of the crests of EIA as is characteristic for pre-dawn and early morning hours (11 LT) was observed. On Sept 16th co-seismic ionospheric signatures consistent with defined circular acoustic-gravity wave and different shock-acoustic waves were also observed. GPS TEC and deformation studies were computed from 48 GPS stations (2013-2015) of National Seismological Center of Chile (CSN) GPS network. A transient signal of deformation has been observed a week in advance correlated with ground-based magnetometers ULF signal fluctuation from closest to the epicenter station from the SAMBA-AMBER network. The characteristics of the observed pre-, and co - seismic transient signals associated with the M8.3 of Illapel, Chile 2015 earthquake suggested that they follow general temporal-spatial evolution pattern, which has been seen in other large earthquakes worldwide.

EIT Noise Resonance Power Broadening: a probe for coherence dynamics

NASA Astrophysics Data System (ADS)

Crescimanno, Michael; O'Leary, Shannon; Snider, Charles

2012-06-01

EIT noise correlation spectroscopy holds promise as a simple, robust method for performing high resolution spectroscopy used in devices as diverse as magnetometers and clocks. One useful feature of these noise correlation resonances is that they do not power broaden with the EIT window. We report on measurements of the eventual power broadening (at higher optical powers) of these resonances and a simple, quantitative theoretical model that relates the observed power broadening slope with processes such as two-photon detuning gradients and coherence diffusion. These processes reduce the ground state coherence relative to that of a homogeneous system, and thus the power broadening slope of the EIT noise correlation resonance may be a simple, useful probe for coherence dynamics.

Electronic systems for the new multichannel spectrometer at Sacramento Peak.

NASA Technical Reports Server (NTRS)

Hobbs, R. W.; Harris, G. D.; Epstein, G.

1972-01-01

Description of the design features and operation of a new multichannel solar spectrometer to be used for ground-based observations of active regions whose X-ray and EUV emissions are studied by the OSO-H and other satellites. The electronic systems associated with the instrument include (1) an electrooptical guider controlled by a punched paper tape capable of making raster scans of selected portions of the solar disk, (2) a programmer unit that applies paper-tape commands to various portions of the instrument, (3) a closed-loop servosystem for the vacuum heliostat, (4) stepping motor controls for spectral scans, (5) a 40-channel photomultiplier readout, and (6) a magnetometer. Preliminary solar observations indicate satisfactory performance of the system.

Inferring electric fields and currents from ground magnetometer data - A test with theoretically derived inputs

NASA Technical Reports Server (NTRS)

Wolf, R. A.; Kamide, Y.

1983-01-01

Advanced techniques considered by Kamide et al. (1981) seem to have the potential for providing observation-based high time resolution pictures of the global ionospheric current and electric field patterns for interesting events. However, a reliance on the proposed magnetogram-inversion schemes for the deduction of global ionospheric current and electric field patterns requires proof that reliable results are obtained. 'Theoretical' tests of the accuracy of the magnetogram inversion schemes have, therefore, been considered. The present investigation is concerned with a test, involving the developed KRM algorithm and the Rice Convection Model (RCM). The test was successful in the sense that there was overall agreement between electric fields and currents calculated by the RCM and KRM schemes.

Empirical Determination of Efficient Sensing Frequencies for Magnetometer-Based Continuous Human Contact Monitoring.

PubMed

Kuk, Seungho; Kim, Junha; Park, Yongtae; Kim, Hyogon

2018-04-27

The high linear correlation between the smartphone magnetometer readings in close proximity can be exploited for physical human contact detection, which could be useful for such applications as infectious disease contact tracing or social behavior monitoring. Alternative approaches using other capabilities in smartphones have aspects that do not fit well with the human contact detection. Using Wi-Fi or cellular fingerprints have larger localization errors than close human contact distances. Bluetooth beacons could reveal the identity of the transmitter, threatening the privacy of the user. Also, using sensors such as GPS does not work for indoor contacts. However, the magnetometer correlation check works best in human contact distances that matter in infectious disease transmissions or social interactions. The omni-present geomagnetism makes it work both indoors and outdoors, and the measured magnetometer values do not easily reveal the identity and the location of the smartphone. One issue with the magnetometer-based contact detection, however, is the energy consumption. Since the contacts can take place anytime, the magnetometer sensing and recording should be running continuously. Therefore, how we address the energy requirement for the extended and continuous operation can decide the viability of the whole idea. However, then, we note that almost all existing magnetometer-based applications such as indoor location and navigation have used high sensing frequencies, ranging from 10 Hz to 200 Hz. At these frequencies, we measure that the time to complete battery drain in a typical smartphone is shortened by three to twelve hours. The heavy toll raises the question as to whether the magnetometer-based contact detection can avoid such high sensing rates while not losing the contact detection accuracy. In order to answer the question, we conduct a measurement-based study using independently produced magnetometer traces from three different countries. Specifically, we gradually remove high frequency components in the traces, while observing the correlation changes. As a result, we find that the human coexistence detection indeed tends to be no less, if not more, effective at the sampling frequency of 1 Hz or even less. This is because unlike the other applications that require centimeter-level precision, the human contacts detected anywhere within a couple of meters are valid for our purpose. With the typical smartphone battery capacity and at the 1 Hz sensing, the battery consumption is well below an hour, which is smaller by more than two hours compared with 10 Hz sampling and by almost eleven hours compared with 200 Hz sampling. With other tasks running simultaneously on smartphones, the energy saving aspect will only become more critical. Therefore, we conclude that sensing the ambient magnetic field at 1 Hz is sufficient for the human contact monitoring purpose. We expect that this finding will have a significant practicability implication in the smartphone magnetometer-based contact monitoring applications in general.

Empirical Determination of Efficient Sensing Frequencies for Magnetometer-Based Continuous Human Contact Monitoring

PubMed Central

Kuk, Seungho; Kim, Junha; Park, Yongtae; Kim, Hyogon

2018-01-01

The high linear correlation between the smartphone magnetometer readings in close proximity can be exploited for physical human contact detection, which could be useful for such applications as infectious disease contact tracing or social behavior monitoring. Alternative approaches using other capabilities in smartphones have aspects that do not fit well with the human contact detection. Using Wi-Fi or cellular fingerprints have larger localization errors than close human contact distances. Bluetooth beacons could reveal the identity of the transmitter, threatening the privacy of the user. Also, using sensors such as GPS does not work for indoor contacts. However, the magnetometer correlation check works best in human contact distances that matter in infectious disease transmissions or social interactions. The omni-present geomagnetism makes it work both indoors and outdoors, and the measured magnetometer values do not easily reveal the identity and the location of the smartphone. One issue with the magnetometer-based contact detection, however, is the energy consumption. Since the contacts can take place anytime, the magnetometer sensing and recording should be running continuously. Therefore, how we address the energy requirement for the extended and continuous operation can decide the viability of the whole idea. However, then, we note that almost all existing magnetometer-based applications such as indoor location and navigation have used high sensing frequencies, ranging from 10 Hz to 200 Hz. At these frequencies, we measure that the time to complete battery drain in a typical smartphone is shortened by three to twelve hours. The heavy toll raises the question as to whether the magnetometer-based contact detection can avoid such high sensing rates while not losing the contact detection accuracy. In order to answer the question, we conduct a measurement-based study using independently produced magnetometer traces from three different countries. Specifically, we gradually remove high frequency components in the traces, while observing the correlation changes. As a result, we find that the human coexistence detection indeed tends to be no less, if not more, effective at the sampling frequency of 1 Hz or even less. This is because unlike the other applications that require centimeter-level precision, the human contacts detected anywhere within a couple of meters are valid for our purpose. With the typical smartphone battery capacity and at the 1 Hz sensing, the battery consumption is well below an hour, which is smaller by more than two hours compared with 10 Hz sampling and by almost eleven hours compared with 200 Hz sampling. With other tasks running simultaneously on smartphones, the energy saving aspect will only become more critical. Therefore, we conclude that sensing the ambient magnetic field at 1 Hz is sufficient for the human contact monitoring purpose. We expect that this finding will have a significant practicability implication in the smartphone magnetometer-based contact monitoring applications in general. PMID:29702586

The effect of body mass and sex on the accuracy of respiratory magnetometers for measurement of end-expiratory lung volumes.

PubMed

Avraam, Joanne; Bourke, Rosie; Trinder, John; Nicholas, Christian L; Brazzale, Danny; O'Donoghue, Fergal J; Rochford, Peter D; Jordan, Amy S

2016-11-01

Respiratory magnetometers are increasingly being used in sleep studies to measure changes in end-expiratory lung volume (EELV), including in obese obstructive sleep apnea patients. Despite this, the accuracy of magnetometers has not been confirmed in obese patients nor compared between sexes. Thus we compared spirometer-measured and magnetometer-estimated lung volume and tidal volume changes during voluntary end-expiratory lung volume changes of 1.5, 1, and 0.5 l above and 0.5 l below functional respiratory capacity in supine normal-weight [body mass index (BMI) < 25 kg/m] and healthy obese (BMI > 30 kg/m) men and women. Two different magnetometer calibration techniques proposed by Banzett et al. [Banzett RB, Mahan ST, Garner DM, Brughera A, Loring SH. J Appl Physiol (1985) 79: 2169-2176, 1995] and Sackner et al. [Sackner MA, Watson H, Belsito AS, Feinerman D, Suarez M, Gonzalez G, Bizousky F, Krieger B. J Appl Physiol (1985) 66: 410-420, 1989] were assessed. Across all groups and target volumes, magnetometers overestimated spirometer-measured EELV by ~65 ml (<0.001) with no difference between techniques (0.07). The Banzett method overestimated the spirometer EELV change in normal-weight women for all target volumes except +0.5 l, whereas no differences between mass or sex groups were observed for the Sackner technique. The variability of breath-to-breath measures of EELV was significantly higher for obese compared with nonobese subjects and was higher for the Sackner than Banzett technique. On the other hand, for tidal volume, both calibration techniques underestimated spirometer measurements (<0.001), with the underestimation being more marked for the Banzett than Sackner technique (0.03), in obese than normal weight (<0.001) and in men than in women (0.003). These results indicate that both body mass and sex affect the accuracy of respiratory magnetometers in measuring EELV and tidal volume. Copyright © 2016 the American Physiological Society.

Solid-State Multimission Magnetometer (SSM(3)): Application to Groundwater Exploration on Mars

NASA Technical Reports Server (NTRS)

Grimm, Robert E.

2002-01-01

This report describes work to develop solid-state magnetometers using magnetoresistive thin films, low-frequency electric-field measurements, and methods for electromagnetic detection of water and ice in the subsurface of Mars.

The Absolute Vector Magnetometers on Board Swarm, Lessons Learned From Two Years in Space.

NASA Astrophysics Data System (ADS)

Hulot, G.; Leger, J. M.; Vigneron, P.; Brocco, L.; Olsen, N.; Jager, T.; Bertrand, F.; Fratter, I.; Sirol, O.; Lalanne, X.

2015-12-01

ESA's Swarm satellites carry 4He absolute magnetometers (ASM), designed by CEA-Léti and developed in partnership with CNES. These instruments are the first-ever space-born magnetometers to use a common sensor to simultaneously deliver 1Hz independent absolute scalar and vector readings of the magnetic field. They have provided the very high accuracy scalar field data nominally required by the mission (for both science and calibration purposes, since each satellite also carries a low noise high frequency fluxgate magnetometer designed by DTU), but also very useful experimental absolute vector data. In this presentation, we will report on the status of the instruments, as well as on the various tests and investigations carried out using these experimental data since launch in November 2013. In particular, we will illustrate the advantages of flying ASM instruments on space-born magnetic missions for nominal data quality checks, geomagnetic field modeling and science objectives.

Comprehensive Evaluation of Attitude and Orbit Estimation Using Actual Earth Magnetic Field Data

NASA Technical Reports Server (NTRS)

Deutschmann, Julie K.; Bar-Itzhack, Itzhack Y.

2000-01-01

A single, augmented Extended Kalman Filter (EKF), which simultaneously and autonomously estimates spacecraft attitude and orbit has been developed and successfully tested with real magnetometer and gyro data only. Because the earth magnetic field is a function of time and position, and because time is known quite precisely, the differences between the computed and measured magnetic field components, as measured by the magnetometers throughout the entire spacecraft orbit, are a function of both orbit and attitude errors. Thus, conceivably these differences could be used to estimate both orbit and attitude; an observability study validated this assumption. The results of testing the EKF with actual magnetometer and gyro data, from four satellites supported by the NASA Goddard Space Flight Center (GSFC) Guidance, Navigation, and Control Center, are presented and evaluated. They confirm the assumption that a single EKF can estimate both attitude and orbit when using gyros and magnetometers only.

A high-sensitivity tunable two-beam fiber-coupled high-density magnetometer with laser heating

DOE PAGES

Savukov, Igor Mykhaylovich; Boshier, Malcolm Geoffrey

2016-10-13

Atomic magnetometers (AM) are finding many applications in biomagnetism, national security, industry, and science. Fiber-coupled (FC) designs promise to make them compact and flexible for operation. Most FC designs are based on a single-beam configuration or electrical heating. Here, we demonstrate a two-beam FC AM with laser heating that has 5 fT/Hz 1/2 sensitivity at low frequency (50 Hz), which is higher than that of other fiber-coupled magnetometers and can be improved to the sub-femtotesla level. Here, this magnetometer is widely tunable from DC to very high frequencies (as high as 100 MHz; the only issue might be the applicationmore » of a suitable uniform and stable bias field) with a sensitivity under 10 fT/Hz 1/2 and can be used for magneto-encephalography (MEG), magneto-cardiography (MCG), underground communication, ultra-low MRI/NMR, NQR detection, and other applications.« less

Ultralow field NMR spectrometer with an atomic magnetometer near room temperature

NASA Astrophysics Data System (ADS)

Liu, Guobin; Li, Xiaofeng; Sun, Xianping; Feng, Jiwen; Ye, Chaohui; Zhou, Xin

2013-12-01

We present a Cs atomic magnetometer with a sensitivity of 150 fT/Hz1/2 operating near room temperature. The nuclear magnetic resonance (NMR) signal of 125 μL tap water was detected at an ultralow magnetic field down to 47 nT, with the signal-to-noise ratio (SNR) of the NMR signal approaching 50 after eight averages. Relaxivity experiments with a Gd(DTPA) contrast agent in zero field were performed, in order to show the magnetometer's ability to measure spin-lattice relaxation time with high accuracy. This demonstrates the feasibility of an ultralow field NMR spectrometer based on a Cs atomic magnetometer, which has a low working temperature, short data acquisition time and high sensitivity. This kind of NMR spectrometer has great potential in applications such as chemical analysis and magnetic relaxometry detection in ultralow or zero fields.

Search for exotic spin-dependent interactions with a spin-exchange relaxation-free magnetometer

DOE PAGES

Chu, Pinghan; Kim, Young Jin; Savukov, Igor Mykhaylovich

2016-08-15

We propose a novel experimental approach to explore exotic spin-dependent interactions using a spin-exchange relaxation-free (SERF) magnetometer, the most sensitive noncryogenic magnetic-field sensor. This approach studies the interactions between optically polarized electron spins located inside a vapor cell of the SERF magnetometer and unpolarized or polarized particles of external solid-state objects. The coupling of spin-dependent interactions to the polarized electron spins of the magnetometer induces the tilt of the electron spins, which can be detected with high sensitivity by a probe laser beam similarly as an external magnetic field. Lastly, we estimate that by moving unpolarized or polarized objects nextmore » to the SERF Rb vapor cell, the experimental limit to the spin-dependent interactions can be significantly improved over existing experiments, and new limits on the coupling strengths can be set in the interaction range below 10 –2 m.« less

NQR detection of explosive simulants using RF atomic magnetometers

NASA Astrophysics Data System (ADS)

Monti, Mark C.; Alexson, Dimitri A.; Okamitsu, Jeffrey K.

2016-05-01

Nuclear Quadrupole Resonance (NQR) is a highly selective spectroscopic method that can be used to detect and identify a number of chemicals of interest to the defense, national security, and law enforcement community. In the past, there have been several documented attempts to utilize NQR to detect nitrogen bearing explosives using induction sensors to detect the NQR RF signatures. We present here our work on the NQR detection of explosive simulants using optically pumped RF atomic magnetometers. RF atomic magnetometers can provide an order of magnitude (or more) improvement in sensitivity versus induction sensors and can enable mitigation of RF interference, which has classically has been a problem for conventional NQR using induction sensors. We present the theory of operation of optically pumped RF atomic magnetometers along with the result of laboratory work on the detection of explosive simulant material. An outline of ongoing work will also be presented along with a path for a fieldable detection system.

Versatile magnetometer assembly for characterizing magnetic properties of nanoparticles.

PubMed

Araujo, J F D F; Bruno, A C; Louro, S R W

2015-10-01

We constructed a versatile magnetometer assembly for characterizing iron oxide nanoparticles. The magnetometer can be operated at room temperature or inside a cryocooler at temperatures as low as 6 K. The magnetometer's sensor can be easily exchanged and different detection electronics can be used. We tested the assembly with a non-cryogenic commercial Hall sensor and a benchtop multimeter in a four-wire resistance measurement scheme. A magnetic moment sensitivity of 8.5 × 10(-8) Am(2) was obtained with this configuration. To illustrate the capability of the assembly, we synthesized iron oxide nanoparticles coated with different amounts of a triblock copolymer, Pluronic F-127, and characterized their magnetic properties. We determined that the polymer coating does not affect the magnetization of the particles at room temperature and demonstrates that it is possible to estimate the average size of coating layers from measurements of the magnetic field of the sample.

Versatile magnetometer assembly for characterizing magnetic properties of nanoparticles

NASA Astrophysics Data System (ADS)

Araujo, J. F. D. F.; Bruno, A. C.; Louro, S. R. W.

2015-10-01

We constructed a versatile magnetometer assembly for characterizing iron oxide nanoparticles. The magnetometer can be operated at room temperature or inside a cryocooler at temperatures as low as 6 K. The magnetometer's sensor can be easily exchanged and different detection electronics can be used. We tested the assembly with a non-cryogenic commercial Hall sensor and a benchtop multimeter in a four-wire resistance measurement scheme. A magnetic moment sensitivity of 8.5 × 10-8 Am2 was obtained with this configuration. To illustrate the capability of the assembly, we synthesized iron oxide nanoparticles coated with different amounts of a triblock copolymer, Pluronic F-127, and characterized their magnetic properties. We determined that the polymer coating does not affect the magnetization of the particles at room temperature and demonstrates that it is possible to estimate the average size of coating layers from measurements of the magnetic field of the sample.

Development of a Strain Energy Deployable Boom for the Space Technology 5 Mission

NASA Technical Reports Server (NTRS)

Meyers, Stew; Sturm, James

2004-01-01

The Space Technology 5 (ST5) mission is one of a series of technology demonstration missions for the New Millennium Program. This mission will fly three fully functional 25-kilogram micro-class spacecraft in formation through the Earth's magnetosphere; the primary science instrument is a very sensitive magnetometer. The constraints of a 25-kg Micosat resulted in a spin stabilized, octagonal spacecraft that is 30 cm tall by 50 cm diameter and has state-of-the-art solar cells on all eight sides. A non-magnetic boom was needed to place the magnetometer as far from the spacecraft and its residual magnetic fields as possible. The ST-5 spacecraft is designed to be spun up and released from its deployer with the boom and magnetometer stowed for later release. The deployer is the topic of another paper. This paper describes the development efforts and resulting self-deploying magnetometer boom.

Development of a Strain Energy Deployable Boom for the Space Technology 5 Mission

NASA Technical Reports Server (NTRS)

Meyers, Stew; Sturm, James

2004-01-01

The Space Technology 5 (ST5) mission is one of a series of technology demonstration missions for the New Millennium Program. This mission will fly three fully functional 25 kilogram micro class spacecraft in formation through the Earth s magnetosphere; the primary science instrument is a very sensitive magnetometer. The constraints of a 25 kg "Micosat" resulted in a spin stabilized, octagonal spacecraft that is 30 cm tall by 50 cm diameter and has state of the art solar cells on all eight sides. A non-magnetic boom was needed to place the magnetometer as far from the spacecraft and its residual magnetic fields as possible. The ST-5 spacecraft is designed to be spun up and released from its deployer with the boom and magnetometer stowed for later release. The deployer is the topic of another paper, This paper describes the development efforts and resulting self-deploying magnetometer boom.

Effect of second harmonic in pulse-width-modulation-based DAC for feedback of digital fluxgate magnetometer

NASA Astrophysics Data System (ADS)

Belyayev, Serhiy; Ivchenko, Nickolay

2018-04-01

Digital fluxgate magnetometers employ processing of the measured pickup signal to produce the value of the compensation current. Using pulse-width modulation with filtering for digital to analog conversion is a convenient approach, but it can introduce an intrinsic source of nonlinearity, which we discuss in this design note. A code shift of one least significant bit changes the second harmonic content of the pulse train, which feeds into the pick-up signal chain despite the heavy filtering. This effect produces a code-dependent nonlinearity. This nonlinearity can be overcome by the specific design of the timing of the pulse train signal. The second harmonic is suppressed if the first and third quarters of the excitation period pulse train are repeated in the second and fourth quarters. We demonstrate this principle on a digital magnetometer, achieving a magnetometer noise level corresponding to that of the sensor itself.

Determination of the accuracy and operating constants in a digitally biased ring core magnetometer

USGS Publications Warehouse

Green, A.W.

1990-01-01

By using a very stable voltage reference and a high precision digital-to-analog converter to set bias in digital increments, the inherently high stability and accuracy of a ring core magnetometer can be significantly enhanced. In this case it becomes possible to measure not only variations about the bias level, but to measure the entire value of the field along each magnetometer sensing axis in a nearly absolute sense. To accomplish this, one must accurately determine the value of the digital bias increment for each axis, the zero field offset value for each axis, the scale values, and the transfer coefficients (or nonorthogonality angles) for pairs of axes. This determination can be carried out very simply, using only the Earth's field, a proton magnetometer, and a tripod-mounted fixture which is capable of rotations about two axes that are mutually perpendicular to the Earth's magnetic field vector. ?? 1990.

A High-Sensitivity Tunable Two-Beam Fiber-Coupled High-Density Magnetometer with Laser Heating

PubMed Central

Savukov, Igor; Boshier, Malcolm G.

2016-01-01

Atomic magnetometers (AM) are finding many applications in biomagnetism, national security, industry, and science. Fiber-coupled (FC) designs promise to make them compact and flexible for operation. Most FC designs are based on a single-beam configuration or electrical heating. Here, we demonstrate a two-beam FC AM with laser heating that has 5 fT/Hz1/2 sensitivity at low frequency (50 Hz), which is higher than that of other fiber-coupled magnetometers and can be improved to the sub-femtotesla level. This magnetometer is widely tunable from DC to very high frequencies (as high as 100 MHz; the only issue might be the application of a suitable uniform and stable bias field) with a sensitivity under 10 fT/Hz1/2 and can be used for magneto-encephalography (MEG), magneto-cardiography (MCG), underground communication, ultra-low MRI/NMR, NQR detection, and other applications. PMID:27754358

A Near-real-time Data Transport System for Selected Stations in the Magnetometer Array for Cusp and Cleft Studies (MACCS)

NASA Astrophysics Data System (ADS)

Engebretson, M. J.; Valentic, T. A.; Stehle, R. H.; Hughes, W. J.

2004-05-01

The Magnetometer Array for Cusp and Cleft Studies (MACCS) is a two-dimensional array of eight fluxgate magnetometers that was established in 1992-1993 in the Eastern Canadian Arctic from 75° to over 80° MLAT to study electrodynamic interactions between the solar wind and Earth's magnetosphere and high-latitude ionosphere. A ninth site in Nain, Labrador, extends coverage down to 66° between existing Canadian and Greenland stations. Originally designed as part of NSF's GEM (Geospace Environment Modeling) Program, MACCS has contributed to the study of transients and waves at the magnetospheric boundary and in the near-cusp region as well as to large, cooperative, studies of ionospheric convection and substorm processes. Because of the limitations of existing telephone lines to each site, it has not been possible to economically access MACCS data promptly; instead, each month's collected data is recorded and mailed to the U.S. for processing and eventual posting on a publicly-accessible web site, http://space.augsburg.edu/space. As part of its recently renewed funding, NSF has supported the development of a near-real-time data transport system using the Iridium satellite network, which will be implemented at two MACCS sites in summer 2004. At the core of the new MACCS communications system is the Data Transport Network, software developed with NSF-ITR funding to automate the transfer of scientific data from remote field stations over unreliable, bandwidth-constrained network connections. The system utilizes a store-and-forward architecture based on sending data files as attachments to Usenet messages. This scheme not only isolates the instruments from network outages, but also provides a consistent framework for organizing and accessing multiple data feeds. Client programs are able to subscribe to data feeds to perform tasks such as system health monitoring, data processing, web page updates and e-mail alerts. The MACCS sites will employ the Data Transport Network on a small local Linux-based computer connected to an Iridium transceiver. Between 3-5Mb of data a day will be collected from the magnetometers and delivered in near-real-time for automatic distribution to modelers and index developers. More information about the Data Transport Network can be found at http://transport.sri.com/TransportDevel .

Traveling magnetopause distortion related to a large-scale magnetosheath plasma jet: THEMIS and ground-based observations

NASA Astrophysics Data System (ADS)

Dmitriev, A. V.; Suvorova, A. V.

2012-08-01

Here, we present a case study of THEMIS and ground-based observations of the perturbed dayside magnetopause and the geomagnetic field in relation to the interaction of an interplanetary directional discontinuity (DD) with the magnetosphere on 16 June 2007. The interaction resulted in a large-scale local magnetopause distortion of an "expansion - compression - expansion" (ECE) sequence that lasted for ˜15 min. The compression was caused by a very dense, cold, and fast high-βmagnetosheath plasma flow, a so-called plasma jet, whose kinetic energy was approximately three times higher than the energy of the incident solar wind. The plasma jet resulted in the effective penetration of magnetosheath plasma inside the magnetosphere. A strong distortion of the Chapman-Ferraro current in the ECE sequence generated a tripolar magnetic pulse "decrease - peak- decrease" (DPD) that was observed at low and middle latitudes by some ground-based magnetometers of the INTERMAGNET network. The characteristics of the ECE sequence and the spatial-temporal dynamics of the DPD pulse were found to be very different from any reported patterns of DD interactions with the magnetosphere. The observed features only partially resembled structures such as FTE, hot flow anomalies, and transient density events. Thus, it is difficult to explain them in the context of existing models.

Digital fluxgate magnetometer: design notes

NASA Astrophysics Data System (ADS)

Belyayev, Serhiy; Ivchenko, Nickolay

2015-12-01

We presented an approach to understanding the performance of a fully digital fluxgate magnetometer. All elements of the design are important for the performance of the instrument, and the presence of the digital feed-back loop introduces certain peculiarities affecting the noise and dynamic performance of the instrument. Ultimately, the quantisation noise of the digital to analogue converter is found to dominate the noise of the current design, although noise shaping alleviates its effect to some extent. An example of magnetometer measurements on board a sounding rocket is presented, and ways to further improve the performance of the instrument are discussed.

A LEO Satellite Navigation Algorithm Based on GPS and Magnetometer Data

NASA Technical Reports Server (NTRS)

Deutschmann, Julie; Bar-Itzhack, Itzhack; Harman, Rick; Bauer, Frank H. (Technical Monitor)

2000-01-01

The Global Positioning System (GPS) has become a standard method for low cost onboard satellite orbit determination. The use of a GPS receiver as an attitude and rate sensor has also been developed in the recent past. Additionally, focus has been given to attitude and orbit estimation using the magnetometer, a low cost, reliable sensor. Combining measurements from both GPS and a magnetometer can provide a robust navigation system that takes advantage of the estimation qualities of both measurements. Ultimately a low cost, accurate navigation system can result, potentially eliminating the need for more costly sensors, including gyroscopes.

Design and development of a magnetometer calibration device

NASA Astrophysics Data System (ADS)

Angelopoulos, S.

2017-12-01

This paper describes the development of a new magnetometer calibration device, which is able to provide accuracy of 1fT/√Hz. The mentioned device is able to eliminate the ambient magnetic field, using an active shielding technique. This can be achieved by the use of a solenoid or a pair of Helmholtz coils. In order to measure the existing magnetic field, it is necessary to develop and use accurate magnetometers with amorphous ribbons as core magnetic materials. The whole system works as a closed-loop system, which is able to control and adjust the produced counter magnetic field.

Electromagnetic induction imaging with a radio-frequency atomic magnetometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deans, Cameron; Marmugi, Luca, E-mail: l.marmugi@ucl.ac.uk; Hussain, Sarah

2016-03-07

We report on a compact, tunable, and scalable to large arrays imaging device, based on a radio-frequency optically pumped atomic magnetometer operating in magnetic induction tomography modality. Imaging of conductive objects is performed at room temperature, in an unshielded environment and without background subtraction. Conductivity maps of target objects exhibit not only excellent performance in terms of shape reconstruction but also demonstrate detection of sub-millimetric cracks and penetration of conductive barriers. The results presented here demonstrate the potential of a future generation of imaging instruments, which combine magnetic induction tomography and the unmatched performance of atomic magnetometers.

Characterization and demonstration results of a SQUID magnetometer system developed for geomagnetic field measurements

NASA Astrophysics Data System (ADS)

Kawai, J.; Miyamoto, M.; Kawabata, M.; Nosé, M.; Haruta, Y.; Uehara, G.

2017-08-01

We characterized a low temperature superconducting quantum interference device (SQUID) magnetometer system developed for high-sensitivity geomagnetic field measurement, and demonstrated the detection of weak geomagnetic signals. The SQUID magnetometer system is comprised of three-axis SQUID magnetometers housed in a glass fiber reinforced plastic cryostat, readout electronics with flux locked loop (FLL), a 24-bit data logger with a global positioning system and batteries. The system noise was approximately 0.2 pT √Hz- 1/2 in the 1-50 Hz frequency range. This performance was determined by including the thermal noise and the shielding effect of the copper shield, which covered the SQUID magnetometers to eliminate high-frequency interference. The temperature drift of the system was ˜0.8 pT °C- 1 in an FLL operation. The system operated for a month using 33 l liquid helium. Using this system, we performed the measurements of geomagnetic field in the open-air, far away from the city. The system could detect weak geomagnetic signals such as the Schumann resonance with sixth harmonics, and the ionospheric Alfvén resonance appearing at night, for the north-south and east-west components of the geomagnetic field. We confirm that the system was capable of high-sensitivity measurement of the weak geomagnetic activities.

Ultra-sensitive atomic magnetometer for studying magnetization fields produced by hyperpolarized helium-3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zou, Sheng; Zhang, Hong; Fang, Jian-cheng, E-mail: fangjiancheng@buaa.edu.cn

2016-04-14

An ingenious approach to acquire the absolute magnetization fields produced by polarized atoms has been presented in this paper. The method was based on detection of spin precession signal of the hyperpolarized helium-3 with ultra-sensitive atomic magnetometer of potassium by referring to time-domain analysis. At first, dynamic responses of the mixed spin ensembles in the presence of variant external magnetic fields have been analyzed by referring to the Bloch equation. Subsequently, the relevant equipment was established to achieve the functions of hyperpolarizing helium-3 and detecting the precession of spin-polarized noble gas. By analyzing the transient response of the magnetometer inmore » time domain, we obtained the relevant damping ratio and natural frequency. When the value of damping ratio reached the maximum value of 0.0917, the combined atomic magnetometer was in equilibrium. We draw a conclusion from the steady response: the magnetization fields of the polarized electrons and the hyperpolarized nuclei were corresponding 16.12 nT and 90.74 nT. Under this situation, the nuclear magnetization field could offset disturbing magnetic fields perpendicular to the orientation of the electronic polarization, and it preserved the electronic spin staying in a stable axis. Therefore, the combined magnetometer was particularly attractive for inertial measurements.« less

Seismo-induced effects in the near-earth space: Combined ground and space investigations as a contribution to earthquake prediction

NASA Astrophysics Data System (ADS)

Sgrigna, V.; Buzzi, A.; Conti, L.; Picozza, P.; Stagni, C.; Zilpimiani, D.

2007-02-01

The paper aims at giving a few methodological suggestions in deterministic earthquake prediction studies based on combined ground-based and space observations of earthquake precursors. Up to now what is lacking is the demonstration of a causal relationship with explained physical processes and looking for a correlation between data gathered simultaneously and continuously by space observations and ground-based measurements. Coordinated space and ground-based observations imply available test sites on the Earth surface to correlate ground data, collected by appropriate networks of instruments, with space ones detected on board of LEO satellites. At this purpose a new result reported in the paper is an original and specific space mission project (ESPERIA) and two instruments of its payload. The ESPERIA space project has been performed for the Italian Space Agency and three ESPERIA instruments (ARINA and LAZIO particle detectors, and EGLE search-coil magnetometer) have been built and tested in space. The EGLE experiment started last April 15, 2005 on board the ISS, within the ENEIDE mission. The launch of ARINA occurred on June 15, 2006, on board the RESURS DK-1 Russian LEO satellite. As an introduction and justification to these experiments the paper clarifies some basic concepts and critical methodological aspects concerning deterministic and statistic approaches and their use in earthquake prediction. We also take the liberty of giving the scientific community a few critical hints based on our personal experience in the field and propose a joint study devoted to earthquake prediction and warning.

MAGID-II: a next-generation magnetic unattended ground sensor (UGS)

NASA Astrophysics Data System (ADS)

Walter, Paul A.; Mauriello, Fred; Huber, Philip

2012-06-01

A next generation magnetic sensor is being developed at L-3 Communications, Communication Systems East to enhance the ability of Army and Marine Corps unattended ground sensor (UGS) systems to detect and track targets on the battlefield. This paper describes a magnetic sensor that provides superior detection range for both armed personnel and vehicle targets, at a reduced size, weight, and level of power consumption (SWAP) over currently available magnetic sensors. The design integrates the proven technology of a flux gate magnetometer combined with advanced digital signal processing algorithms to provide the warfighter with a rapidly deployable, extremely low false-alarm-rate sensor. This new sensor improves on currently available magnetic UGS systems by providing not only target detection and direction information, but also a magnetic disturbance readout, indicating the size of the target. The sensor integrates with Government Off-the-Shelf (GOTS) systems such as the United States Army's Battlefield Anti-Intrusion System (BAIS) and the United States Marine Corps Tactical Remote Sensor System (TRSS). The system has undergone testing by the US Marine Corps, as well as extensive company testing. Results from these field tests are given.

The Future of Operational Space Weather Observations

NASA Astrophysics Data System (ADS)

Berger, T. E.

2015-12-01

We review the current state of operational space weather observations, the requirements for new or evolved space weather forecasting capablities, and the relevant sections of the new National strategy for space weather developed by the Space Weather Operations, Research, and Mitigation (SWORM) Task Force chartered by the Office of Science and Technology Policy of the White House. Based on this foundation, we discuss future space missions such as the NOAA space weather mission to the L1 Lagrangian point planned for the 2021 time frame and its synergy with an L5 mission planned for the same period; the space weather capabilities of the upcoming GOES-R mission, as well as GOES-Next possiblities; and the upcoming COSMIC-2 mission for ionospheric observations. We also discuss the needs for ground-based operational networks to supply mission critical and/or backup space weather observations including the NSF GONG solar optical observing network, the USAF SEON solar radio observing network, the USGS real-time magnetometer network, the USCG CORS network of GPS receivers, and the possibility of operationalizing the world-wide network of neutron monitors for real-time alerts of ground-level radiation events.

Aeromagnetic Surveying with a Rotary-Wing Unmanned Aircraft System: A Case Study from a Zinc Deposit in Nash Creek, New Brunswick, Canada

NASA Astrophysics Data System (ADS)

Cunningham, Michael; Samson, Claire; Wood, Alan; Cook, Ian

2017-12-01

Unmanned aircraft systems (UASs) have been under rapid development for applications in the mineral exploration industry, mainly for aeromagnetic surveying. They provide improved detection of smaller, deeper and weaker magnetic targets. A traditional system flying an altitude of 100 m above ground level (AGL) can detect a spherical ore body with a radius of 16 m and a magnetic susceptibility of 10-4 buried at a depth of 40 m. A UAS flying at an altitude of 50 or 2 m AGL would require the radius to be 11 or 5 m, respectively. A demonstration survey was performed using the SkyLance rotary-wing UAS instrumented with a cesium vapour magnetometer in Nash Creek, New Brunswick, Canada. The UAS flew over a zinc deposit featuring three magnetic anomalies. It acquired repeatable data that compared well with upward continuation maps of ground magnetic data. Dykes or faults that are dipping eastward at 25° and are approximately 1.5 m wide fit the observed response of the three anomalies captured on the UAS magnetic data.

Director of Innovation. Volume 3, November 2009

DTIC Science & Technology

2009-11-01

evaluated at Crimson Vi- per 2009 included the Portable Acoustic Contraband Detector (PACD) and the Fluxgate Magnetometer , two projects from SPAWAR...concealed within the containers. The Fluxgate Magnetometer is a hockey puck-sized sensor head that can detect vehicles and weapons by measuring

Venus Lightning: What We Have Learned from the Venus Express Fluxgate Magnetometer

NASA Astrophysics Data System (ADS)

Russell, C. T.; Strangeway, R. J.; Wei, H. Y.; Zhang, T. L.

2010-03-01

The Venus Express magnetometer sees short (tens of milliseconds) pulses of EM waves in the Venus ionosphere as predicted by the lightning model for the PVO electric pulses. These waves are stronger than similar terrestrial signals produced by lightning.

Magnetic field observations in the near-field the 28 June 1992 Mw 7.3 Landers, California, earthquake

USGS Publications Warehouse

Johnston, M.J.; Mueller, R.J.; Sasai, Yoichi

1994-01-01

Recent reports suggest that large magnetic field changes occur prior to, and during, large earthquakes. Two continuously operating proton magnetometers, LSBM and OCHM, at distances of 17.3 and 24.2 km, respectively, from the epicenter of the 28 June 1992 Mw 7.3 Landers earthquake, recorded data through the earthquake and its aftershocks. These two stations are part of a differentially connected array of proton magnetometers that has been operated along the San Andreas fault since 1976. The instruments have a sensitivity of 0.25 nT or better and transmit data every 10 min through the GOES satellite to the USGS headquarters in Menlo Park, California. Seismomagnetic offsets of −1.2 ± 0.6 and −0.7 ± 0.7 nT were observed at these sites. In comparison, offsets of −0.3 ± 0.2 and −1.3 ± 0.2 nT were observed during the 8 July 1986 ML 5.9 North Palm Springs earthquake, which occurred directly beneath the OCHM magnetometer site. The observations are generally consistent with seismomagnetic models of the earthquake, in which fault geometry and slip have the same from as that determined by either inversion of the seismic data or inversion of geodetically determined ground displacements produced by the earthquake. In these models, right-lateral rupture occurs on connected fault segments in a homogeneous medium with average magnetization of 2 A/m. The fault-slip distribution has roughly the same form as the observed surface rupture, and the total moment release is 1.1 × 1020 Nm. There is no indication of diffusion-like character to the magnetic field offsets that might indicate these effects result from fluid flow phenomena. It thus seems unlikely that these earthquake-generated offsets and those produced by the North Palm Springs earthquake were generated by electrokinetic effects. Also, there are no indications of enhanced low-frequency magnetic noise before the earthquake at frequencies below 0.001 Hz.

A game-theoretic approach for calibration of low-cost magnetometers under noise uncertainty

NASA Astrophysics Data System (ADS)

Siddharth, S.; Ali, A. S.; El-Sheimy, N.; Goodall, C. L.; Syed, Z. F.

2012-02-01

Pedestrian heading estimation is a fundamental challenge in Global Navigation Satellite System (GNSS)-denied environments. Additionally, the heading observability considerably degrades in low-speed mode of operation (e.g. walking), making this problem even more challenging. The goal of this work is to improve the heading solution when hand-held personal/portable devices, such as cell phones, are used for positioning and to improve the heading estimation in GNSS-denied signal environments. Most smart phones are now equipped with self-contained, low cost, small size and power-efficient sensors, such as magnetometers, gyroscopes and accelerometers. A magnetometer needs calibration before it can be properly employed for navigation purposes. Magnetometers play an important role in absolute heading estimation and are embedded in many smart phones. Before the users navigate with the phone, a calibration is invoked to ensure an improved signal quality. This signal is used later in the heading estimation. In most of the magnetometer-calibration approaches, the motion modes are seldom described to achieve a robust calibration. Also, suitable calibration approaches fail to discuss the stopping criteria for calibration. In this paper, the following three topics are discussed in detail that are important to achieve proper magnetometer-calibration results and in turn the most robust heading solution for the user while taking care of the device misalignment with respect to the user: (a) game-theoretic concepts to attain better filter parameter tuning and robustness in noise uncertainty, (b) best maneuvers with focus on 3D and 2D motion modes and related challenges and (c) investigation of the calibration termination criteria leveraging the calibration robustness and efficiency.

A multipoint study of a substorm occurring on 7 December, 1992, and its theoretical implications

NASA Astrophysics Data System (ADS)

Fox, N. J.; Cowley, S. W. H.; Davda, V. N.; Enno, G.; Friis-Christensen, E.; Greenwald, R. A.; Hairston, M. R.; Lester, M.; Lockwood, M.; Lühr, H.; Milling, D. K.; Murphree, J. S.; Pinnock, M.; Reeves, G. D.

1999-11-01

On 7 December 1992, a moderate substorm was observed by a variety of satellites and ground-based instruments. Ionospheric flows were monitored near dusk by the Goose Bay HF radar and near midnight by the EISCAT radar. The observed flows are compared here with magnetometer observations by the IMAGE array in Scandinavia and the two Greenland chains, the auroral distribution observed by Freja and the substorm cycle observations by the SABRE radar, the SAMNET magnetometer array and LANL geosynchronous satellites. Data from Galileo Earth-encounter II are used to estimate the IMF Bz component. The data presented show that the substorm onset electrojet at midnight was confined to closed field lines equatorward of the pre-existing convection reversal boundaries observed in the dusk and midnight regions. No evidence of substantial closure of open flux was detected following this substorm onset. Indeed the convection reversal boundary on the duskside continued to expand equatorward after onset due to the continued presence of strong southward IMF, such that growth and expansion phase features were simultaneously present. Clear indications of closure of open flux were not observed until a subsequent substorm intensification 25 min after the initial onset. After this time, the substorm auroral bulge in the nightside hours propagated well poleward of the pre-existing convection reversal boundary, and strong flow perturbations were observed by the Goose Bay radar, indicative of flows driven by reconnection in the tail.

The Pioneer 11 high-field fluxgate magnetometer

NASA Technical Reports Server (NTRS)

Acuna, M. H.; Ness, N. F.

1973-01-01

The High Field Fluxgate Magnetometer Experiment flow aboard the Pioneer 11 spacecraft to investigate Jupiter's magnetic field is described. The instrument extends the spacecraft's upper limit measurement capability by more than an order of magnitude to 17.3 gauss with minimum power and volume requirements.

A method of determining attitude from magnetometer data only

NASA Technical Reports Server (NTRS)

Natanson, G. A.; Mclaughlin, S. F.; Nicklas, R. C.

1990-01-01

Presented here is a new algorithm to determine attitude using only magnetometer data under the following conditions: (1) internal torques are known and (2) external torques are negligible. Torque-free rotation of a spacecraft in thruster firing acquisition phase and its magnetic despin in the B-dot mode give typical examples of such situations. A simple analytical formula has been derived in the limiting case of a spacecraft rotating with constant angular velocity. The formula has been tested using low-frequency telemetry data for the Earth Radiation Budget Satellite (ERBS) under normal conditions. Observed small oscillation of body-fixed components of the angular velocity vector near their mean values result in relatively minor errors of approximately 5 degrees. More significant errors come from processing digital magnetometer data. Higher resolution of digitized magnetometer measurements would significantly improve the accuracy of this deterministic scheme. Tests of the general version of the developed algorithm for a free-rotating spacecraft and for the B-dot mode are in progress.

In-flight calibration of the spin axis offset of a fluxgate magnetometer with an electron drift instrument

NASA Astrophysics Data System (ADS)

Leinweber, H. K.; Russell, C. T.; Torkar, K.

2012-10-01

We show that the spin axis offset of a fluxgate magnetometer can be calibrated with an electron drift instrument (EDI) and that the required input time interval is relatively short. For missions such as Cluster or the upcoming Magnetospheric Multiscale (MMS) mission the spin axis offset of a fluxgate magnetometer could be determined on an orbital basis. An improvement of existing methods for finding spin axis offsets via comparison of accurate measurements of the field magnitude is presented, that additionally matches the gains of the two instruments that are being compared. The technique has been applied to EDI data from the Cluster Active Archive and fluxgate magnetometer data processed with calibration files also from the Cluster Active Archive. The method could prove to be valuable for the MMS mission because the four MMS spacecraft will only be inside the interplanetary field (where spin axis offsets can be calculated from Alfvénic fluctuations) for short periods of time and during unusual solar wind conditions.

MgB2 magnetometer with a directly coupled pick-up loop

NASA Astrophysics Data System (ADS)

Portesi, C.; Mijatovic, D.; Veldhuis, D.; Brinkman, A.; Monticone, E.; Gonnelli, R. S.

2006-05-01

In this work, we show the results obtained in the fabrication and characterization of an MgB2 magnetometer with a directly coupled pick-up loop. We used an all in situ technique for fabricating magnesium diboride films, which consists of the co-evaporation of B and Mg by means of an e-gun and a resistive heater respectively. Consequently, we realized the superconducting device, which incorporates two nanobridges as weak links in a superconducting loop. The nanobridges were realized by focused ion beam milling; they were 240 nm wide and had a critical current density of 107 A cm-2. The magnetometer was characterized at different temperatures and also measurements of the noise levels have been performed. The device shows Josephson quantum interference up to 20 K and the calculated effective area at low temperatures was 0.24 mm2. The transport properties of the magnetometer allow determining fundamental materials properties of the MgB2 thin films, such as the penetration depth.

A magnetic field measurement technique using a miniature transducer

NASA Technical Reports Server (NTRS)

Fales, C. L., Jr.; Breckenridge, R. A.; Debnam, W. J., Jr.

1974-01-01

The development, fabrication, and application of a magnetometer are described. The magnetometer has a miniature transducer and is capable of automatic scanning. The magnetometer described here is capable of detecting static magnetic fields as low as 1.6 A/m and its transducer has an active area 0.64 mm by 0.76 mm. Thin and rugged, the transducer uses wire, 0.05 mm in diameter, which is plated with a magnetic film, enabling measurement of transverse magnetic fields as close as 0.08 mm from a surface. The magnetometer, which is simple to operate and has a fast response, uses an inexpensive clip-on milliammeter (commonly found in most laboratories) for driving and processing the electrical signals and readout. A specially designed transducer holding mechanism replaces the XY recorder ink pen; this mechanism provides the basis for an automatic scanning technique. The instrument has been applied to the measurements of magnetic fields arising from remanent magnetization in experimental plated-wire memory planes and regions of magnetic activity in geological rock specimens.

A portable Hall magnetometer probe for characterization of magnetic iron oxide nanoparticles

NASA Astrophysics Data System (ADS)

Araujo, Jefferson F. D. F.; Costa, Mateus C.; Louro, Sonia R. W.; Bruno, Antonio C.

2017-03-01

We have built a portable Hall magnetometer probe, for measuring magnetic properties of iron oxide nanoparticles, that can be used for bulk materials and liquid samples as well. The magnetometer probe consists of four voltage-programmable commercial Hall sensors and a thin acrylic plate for positioning the sensors. In order to operate, it needs to be attached to a pole of an electromagnet and connected to an AD converter and a computer. It acquires a complete magnetization curve in a couple of minutes and has a magnetic moment sensitivity of 3.5×10-7 Am2. We tested its performance with magnetic nanoparticles containing an iron oxide core and having coating layers with different sizes. The magnetization results obtained were compared with measurements performed on commercial stand-alone magnetometers, and exhibited errors of about ±0.2 Am2/kg (i.e 0.4%) at saturation and below 0.5 Am2/kg (i.e. 10%) at remanence.

Suppression of the Nonlinear Zeeman Effect and Heading Error in Earth-Field-Range Alkali-Vapor Magnetometers.

PubMed

Bao, Guzhi; Wickenbrock, Arne; Rochester, Simon; Zhang, Weiping; Budker, Dmitry

2018-01-19

The nonlinear Zeeman effect can induce splitting and asymmetries of magnetic-resonance lines in the geophysical magnetic-field range. This is a major source of "heading error" for scalar atomic magnetometers. We demonstrate a method to suppress the nonlinear Zeeman effect and heading error based on spin locking. In an all-optical synchronously pumped magnetometer with separate pump and probe beams, we apply a radio-frequency field which is in phase with the precessing magnetization. This results in the collapse of the multicomponent asymmetric magnetic-resonance line with ∼100  Hz width in the Earth-field range into a single peak with a width of 22 Hz, whose position is largely independent of the orientation of the sensor within a range of orientation angles. The technique is expected to be broadly applicable in practical magnetometry, potentially boosting the sensitivity and accuracy of Earth-surveying magnetometers by increasing the magnetic-resonance amplitude, decreasing its width, and removing the important and limiting heading-error systematic.

Swarm Optimization-Based Magnetometer Calibration for Personal Handheld Devices

PubMed Central

Ali, Abdelrahman; Siddharth, Siddharth; Syed, Zainab; El-Sheimy, Naser

2012-01-01

Inertial Navigation Systems (INS) consist of accelerometers, gyroscopes and a processor that generates position and orientation solutions by integrating the specific forces and rotation rates. In addition to the accelerometers and gyroscopes, magnetometers can be used to derive the user heading based on Earth's magnetic field. Unfortunately, the measurements of the magnetic field obtained with low cost sensors are usually corrupted by several errors, including manufacturing defects and external electro-magnetic fields. Consequently, proper calibration of the magnetometer is required to achieve high accuracy heading measurements. In this paper, a Particle Swarm Optimization (PSO)-based calibration algorithm is presented to estimate the values of the bias and scale factor of low cost magnetometers. The main advantage of this technique is the use of the artificial intelligence which does not need any error modeling or awareness of the nonlinearity. Furthermore, the proposed algorithm can help in the development of Pedestrian Navigation Devices (PNDs) when combined with inertial sensors and GPS/Wi-Fi for indoor navigation and Location Based Services (LBS) applications.

Processing of DMSP magnetic data: Handbook of programs, tapes, and datasets

NASA Technical Reports Server (NTRS)

Langel, R. A.; Sabaka, T. J.; Ridgway, J. R.

1990-01-01

The DMSP F-7 satellite was an operational Air Force meteorological satellite which carried a magnetometer for geophysical measurements. The magnetometer was located within the body of the spacecraft in the presence of large spacecraft fields. In addition to stray magnetic fields, the data have inherent position and time inaccuracies. Algorithms were developed to identify and remove time varying magnetic field noise from the data. These algorithms are embodied in an automated procedure which fits a smooth curve through the data and then identifies outliers and which filters the predominant Fourier component of noise from the data. Techniques developed for Magsat were then modified and used to attempt determination of the spacecraft fields, of any rotation between the magnetometer axes and the spacecraft axes, and of any scale changes within the magnetometer itself. Software setup and usage are documented and program listings are included in the Appendix. The initial and resulting data are archived on magnetic cartridge and the formats are documented.

Magnetism and the interior of the moon. [measured at Apollo landing sites

NASA Technical Reports Server (NTRS)

Dyal, P.; Parkin, C. W.; Daily, W. D.

1974-01-01

During the time period 1961-1972 eleven magnetometers were sent to the moon. The results of lunar magnetometer data analysis are reviewed, with emphasis on the lunar interior. Magnetic fields have been measured on the lunar surface at the Apollo 12, 14, 15, and 16 landing sites. The remanent field values at these sites are given. Satellite and surface measurements show strong evidence that the lunar crust is magnetized over much of the lunar globe. The origin of the lunar remanent field is not yet satisfactorily understood; several source models are presented. Simultaneous data from the Apollo 12 lunar surface magnetometer and the Explorer 35 Ames magnetometer are used to construct a wholemoon hysteresis curve, from which the global lunar permeability is determined. Total iron abundance is calculated for two assumed compositional models of the lunar interior. Other lunar models with a small iron core and with a shallow iron-rich layer are also discussed in light of the measured global permeability.

High-sensitivity operation of single-beam optically pumped magnetometer in a kHz frequency range

DOE PAGES

Savukov, Igor Mykhaylovich; Kim, Y. J.; Shah, V.; ...

2017-02-02

Here, optically pumped magnetometers (OPM) can be used in various applications, from magnetoencephalography to magnetic resonance imaging and nuclear quadrupole resonance (NQR). OPMs provide high sensitivity and have the significant advantage of non-cryogenic operation. To date, many magnetometers have been demonstrated with sensitivity close to 1 fT, but most devices are not commercialized. Most recently, QuSpin developed a model of OPM that is low cost, high sensitivity, and convenient for users, which operates in a single-beam configuration. Here we developed a theory of single-beam (or parallel two-beam) magnetometers and showed that it is possible to achieve good sensitivity beyond theirmore » usual frequency range by tuning the magnetic field. Experimentally we have tested and optimized a QuSpin OPM for operation in the frequency range from DC to 1.7 kHz, and found that the performance was only slightly inferior despite the expected decrease due to deviation from the spin-exchange relaxation-free regime.« less

High-sensitivity operation of single-beam optically pumped magnetometer in a kHz frequency range

DOE Office of Scientific and Technical Information (OSTI.GOV)

Savukov, Igor Mykhaylovich; Kim, Y. J.; Shah, V.

Here, optically pumped magnetometers (OPM) can be used in various applications, from magnetoencephalography to magnetic resonance imaging and nuclear quadrupole resonance (NQR). OPMs provide high sensitivity and have the significant advantage of non-cryogenic operation. To date, many magnetometers have been demonstrated with sensitivity close to 1 fT, but most devices are not commercialized. Most recently, QuSpin developed a model of OPM that is low cost, high sensitivity, and convenient for users, which operates in a single-beam configuration. Here we developed a theory of single-beam (or parallel two-beam) magnetometers and showed that it is possible to achieve good sensitivity beyond theirmore » usual frequency range by tuning the magnetic field. Experimentally we have tested and optimized a QuSpin OPM for operation in the frequency range from DC to 1.7 kHz, and found that the performance was only slightly inferior despite the expected decrease due to deviation from the spin-exchange relaxation-free regime.« less

MAGSAT data processing: A report for investigators

NASA Technical Reports Server (NTRS)

Langel, R. A.; Berbert, J.; Jennings, T.; Horner, R. (Principal Investigator)

1981-01-01

The in-flight attitude and vector magnetometer data bias recovery techniques and results are described. The attitude bias recoveries are based on comparisons with a magnetic field model and are thought to be accurate to 20 arcsec. The vector magnetometer bias recoveries are based on comparisons with the scalar magnetometer data and are thought to be accurate to 3 nT or better. The MAGSAT position accuracy goals of 60 m radially and 300 m horizontally were achieved for all but the last 3 weeks of Magsat lifetime. This claim is supported by ephemeris overlap statistics and by comparisons with ephemerides computed with an independent orbit program using data from an independent tracking network. MAGSAT time determination accuracy is estimated at 1 ms. Several errors in prelaunch assumptions regarding data time tags, which escaped detection in prelaunch data tests, and were discovered and corrected postlaunch are described. Data formats and products, especially the Investigator-B tapes, which contain auxiliary parameters in addition to the basic magnetometer and ephemeris data, are described.

Atomic magnetometer for human magnetoencephalograpy.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwindt, Peter; Johnson, Cort N.

2010-12-01

We have developed a high sensitivity (<5 fTesla/{radical}Hz), fiber-optically coupled magnetometer to detect magnetic fields produced by the human brain. This is the first demonstration of a noncryogenic sensor that could replace cryogenic superconducting quantum interference device (SQUID) magnetometers in magnetoencephalography (MEG) and is an important advance in realizing cost-effective MEG. Within the sensor, a rubidium vapor is optically pumped with 795 laser light while field-induced optical rotations are measured with 780 nm laser light. Both beams share a single optical axis to maximize simplicity and compactness. In collaboration with neuroscientists at The Mind Research Network in Albuquerque, NM, themore » evoked responses resulting from median nerve and auditory stimulation were recorded with the atomic magnetometer and a commercial SQUID-based MEG system with signals comparing favorably. Multi-sensor operation has been demonstrated with two AMs placed on opposite sides of the head. Straightforward miniaturization would enable high-density sensor arrays for whole-head magnetoencephalography.« less

Development of Geomagnetic Monitoring System Using a Magnetometer for the Field

NASA Astrophysics Data System (ADS)

Lee, Young-Cheol; Kim, Sung-Wook; Choi, Eun-Kyeong; Kim, In-Soo

2014-05-01

Three institutes including KMA (Korea Meteorological Administration), KSWC (Korean Space Weather Center) of NRRA (National Radio Research Agency) and KIGAM (Korea Institute of Geoscience and Mineral Resources) are now operating magnetic observatories. Those observatories observe the total intensity and three components of geomagnetic element. This paper comes up with a magnetic monitoring system now under development that uses a magnetometer for field survey. In monitoring magnetic variations in areas (active faults or volcanic regions), more reliable results can be obtained when an array of several magnetometers are used rather than a single magnetometer. In order to establish and operate a magnetometer array, such factors as expenses, convenience of the establishment and operation of the array should be taken into account. This study has come up with a magnetic monitoring system complete with a magnetometer for the field survey of our own designing. A magnetic monitoring system, which is composed of two parts. The one is a field part and the other a data part. The field part is composed of a magnetometer, an external memory module, a power supply and a set of data transmission equipment. The data part is a data server which can store the data transmitted from the field part, analyze the data and provide service to the web. This study has developed an external memory module for ENVI-MAG (Scintrex Ltd.) using an embedded Cortex-M3 board, which can be programmed, attach other functional devices (SD memory cards, GPS antennas for time synchronization, ethernet cards and so forth). The board thus developed can store magnetic measurements up to 8 Gbytes, synchronize with the GPS time and transmit the magnetic measurements to the data server which is now under development. A monitoring system of our own developing was installed in Jeju island, taking measurements throughout Korea. Other parts including a data transfer module, a server and a power supply using solar power will continue to be developed in the days to come. Acknowlegments This work was funded by the Korea Meteorological Administration Research and Development Program under Grant CATER 2006-5074

Probabilistic Multi-Sensor Fusion Based Indoor Positioning System on a Mobile Device

PubMed Central

He, Xiang; Aloi, Daniel N.; Li, Jia

2015-01-01

Nowadays, smart mobile devices include more and more sensors on board, such as motion sensors (accelerometer, gyroscope, magnetometer), wireless signal strength indicators (WiFi, Bluetooth, Zigbee), and visual sensors (LiDAR, camera). People have developed various indoor positioning techniques based on these sensors. In this paper, the probabilistic fusion of multiple sensors is investigated in a hidden Markov model (HMM) framework for mobile-device user-positioning. We propose a graph structure to store the model constructed by multiple sensors during the offline training phase, and a multimodal particle filter to seamlessly fuse the information during the online tracking phase. Based on our algorithm, we develop an indoor positioning system on the iOS platform. The experiments carried out in a typical indoor environment have shown promising results for our proposed algorithm and system design. PMID:26694387

Probabilistic Multi-Sensor Fusion Based Indoor Positioning System on a Mobile Device.

PubMed

He, Xiang; Aloi, Daniel N; Li, Jia

2015-12-14

Nowadays, smart mobile devices include more and more sensors on board, such as motion sensors (accelerometer, gyroscope, magnetometer), wireless signal strength indicators (WiFi, Bluetooth, Zigbee), and visual sensors (LiDAR, camera). People have developed various indoor positioning techniques based on these sensors. In this paper, the probabilistic fusion of multiple sensors is investigated in a hidden Markov model (HMM) framework for mobile-device user-positioning. We propose a graph structure to store the model constructed by multiple sensors during the offline training phase, and a multimodal particle filter to seamlessly fuse the information during the online tracking phase. Based on our algorithm, we develop an indoor positioning system on the iOS platform. The experiments carried out in a typical indoor environment have shown promising results for our proposed algorithm and system design.

Observation and Numerical Simulation of Cavity Mode Oscillations Excited by an Interplanetary Shock

NASA Astrophysics Data System (ADS)

Takahashi, Kazue; Lysak, Robert; Vellante, Massimo; Kletzing, Craig A.; Hartinger, Michael D.; Smith, Charles W.

2018-03-01

Cavity mode oscillations (CMOs) are basic magnetohydrodynamic eigenmodes in the magnetosphere predicted by theory and are expected to occur following the arrival of an interplanetary shock. However, observational studies of shock-induced CMOs have been sparse. We present a case study of a dayside ultralow-frequency wave event that exhibited CMO properties. The event occurred immediately following the arrival of an interplanetary shock at 0829 UT on 15 August 2015. The shock was observed in the solar wind by the Time History of Events and Macroscale Interactions during Substorms-B and -C spacecraft, and magnetospheric ultralow-frequency waves were observed by multiple spacecraft including the Van Allen Probe-A and Van Allen Probe-B spacecraft, which were located in the dayside plasmasphere at L ˜1.4 and L ˜ 2.4, respectively. Both Van Allen Probes spacecraft detected compressional poloidal mode oscillations at ˜13 mHz (fundamental) and ˜26 mHz (second harmonic). At both frequencies, the azimuthal component of the electric field (Eϕ) lagged behind the compressional component of the magnetic field (Bμ) by ˜90°. The frequencies and the Eϕ-Bμ relative phase are in good agreement with the CMOs generated in a dipole magnetohydrodynamic simulation that incorporates a realistic plasma mass density distribution and ionospheric boundary condition. The oscillations were also detected on the ground by the European quasi-Meridional Magnetometer Array, which was located near the magnetic field footprints of the Van Allen Probes spacecraft.

Current Closure in the Auroral Ionosphere: Results from the Auroral Current and Electrodynamics Structure Rocket Mission

NASA Technical Reports Server (NTRS)

Kaeppler, S. R.; Kletzing, C. A.; Bounds, S. R.; Gjerloev, J. W.; Anderson, B. J.; Korth, H.; LaBelle, J. W.; Dombrowski, M. P.; Lessard, M.; Pfaff, R. F.;

Current Closure in the Auroral Ionosphere: Results from the Auroral Current and Electrodynamics Structure Rocket Mission

NASA Technical Reports Server (NTRS)

Kaeppler, S. R.; Kletzing, C. A.; Bounds, S. R.; Gjerloev, J. W.; Anderson, B. J.; Korth, H.; LaBelle, J. W.; Dombrowski, M. P.; Lessard, M.; Pfaff, R. F.;

The Development of Static and Dynamic Models of the Earth’s Radiation Belt Environment through the Study of Plasma Waves, Wave-Particle Interactions and Plasma Number Densities from In Situ Observations in the Earth’s Magnetosphere with the CRRES SPACERAD Instruments

DTIC Science & Technology

1992-01-01

electron number density measurements. Electromagnetic plasma waves below 5.6 Hz are in the frequency range covered by the Fluxgate Magnetometer ...on the part of the spacecraft controllers and for long shadow periods late in 1990 and early 1991. Analyses of the Fluxgate Magnetometer Experiment...remaining was a strong signal between 13 and 13.5 kHz which is due to the drive frequency signal for the Fluxgate Magnetometer Experiment mounted

A low-power, high-sensitivity micromachined optical magnetometer

NASA Astrophysics Data System (ADS)

Mhaskar, R.; Knappe, S.; Kitching, J.

2012-12-01

We demonstrate an optical magnetometer based on a microfabricated 87Rb vapor cell in a micromachined silicon sensor head. The alkali atom density in the vapor cell is increased by heating the cell with light brought to the sensor through an optical fiber, and absorbed by colored filters attached to the cell windows. A second fiber-optically coupled beam optically pumps and interrogates the atoms. The magnetometer operates on 140 mW of heating power and achieves a sensitivity below 20 fT/√Hz throughout most of the frequency band from 15 Hz to 100 Hz. Such a sensor can measure magnetic fields from the human heart and brain.

Comprehensive evaluation of attitude and orbit estimation using real earth magnetic field data

NASA Technical Reports Server (NTRS)

Deutschmann, Julie; Bar-Itzhack, Itzhack

1997-01-01

A single, augmented extended Kalman filter (EKF) which simultaneously and autonomously estimates spacecraft attitude and orbit was developed and tested with simulated and real magnetometer and rate data. Since the earth's magnetic field is a function of time and position, and since time is accurately known, the differences between the computed and measured magnetic field components, as measured by the magnetometers throughout the entire spacecraft's orbit, are a function of orbit and attitude errors. These differences can be used to estimate the orbit and attitude. The test results of the EKF with magnetometer and gyro data from three NASA satellites are presented and evaluated.

High-precision control of static magnetic field magnitude, orientation, and gradient using optically pumped vapour cell magnetometry.

PubMed

Ingleby, S J; Griffin, P F; Arnold, A S; Chouliara, M; Riis, E

2017-04-01

An integrated system of hardware and software allowing precise definition of arbitrarily oriented magnetic fields up to |B| = 1 μT within a five-layer Mumetal shield is described. The system is calibrated with reference to magnetic resonance observed between Zeeman states of the 6S 1/2 F = 4 133 Cs ground state. Magnetic field definition over the full 4π solid angle is demonstrated with one-sigma tolerances in magnitude, orientation, and gradient of δ|B| = 0.94 nT, δθ = 5.9 mrad, and δ|∇B|=13.0 pT/mm, respectively. This field control is used to empirically map M x magnetometer signal amplitude as a function of the static field (B 0 ) orientation.

French language space science educational outreach

NASA Astrophysics Data System (ADS)

Schofield, I.; Masongsong, E. V.; Connors, M. G.

2015-12-01

Athabasca University's AUTUMNX ground-based magnetometer array to measure and report geomagnetic conditions in eastern Canada is located in the heart of French speaking Canada. Through the course of the project, we have had the privilege to partner with schools, universities, astronomy clubs and government agencies across Quebec, all of which operate primarily in French. To acknowledge and serve the needs of our research partners, we have endeavored to produce educational and outreach (EPO) material adapted for francophone audiences with the help of UCLA's department of Earth, Planetary and Space Sciences (EPSS). Not only will this provide greater understanding and appreciation of the geospace environment unique to Quebec and surrounding regions, it strengthens our ties with our francophone, first nations (native Americans) and Inuit partners, trailblazing new paths of research collaboration and inspiring future generations of researchers.

Modulation of auroral electron fluxes in the frequency range 50 kHz to 10 MHz

NASA Technical Reports Server (NTRS)

Spiger, R. J.; Murphree, J. S.; Anderson, H. R.; Loewenstein, R. F.

1976-01-01

A sounding rocket-borne electron detector of high time resolution is used to search for modulation of auroral electron fluxes in the frequency range 50 kHz to 10 MHz and energy range 5-7 keV. Data were telemetered to ground via a 93-kHz subcarrier. A cross-correlation analysis of the data collected indicates low-level modulation near the detection threshold of the instrument. Two U-1 events are observed which are interpreted as indications of modulation. The two modulation events occur during a period of increasing flux for a region marking the boundary between two current sheets detected by the payload magnetometer. The strongest argument against interference contamination is the lack of any observable modulation at times other than those mentioned in the study.

The ESA mission to Comet Halley

NASA Technical Reports Server (NTRS)

Reinhard, R.

1981-01-01

The Europeon Space Agency's approximately Giotto mission plans for a launch in July 1985 with a Halley encounter in mid-March 1986 4 weeks after the comet's perihelion passage. Giotto carries 10 scientific experiments, a camera, neutral, ion and dust mass spectrometers, a dust impact detector system, various plasma analyzers, a magnetometer and an optical probe. The instruments are described, the principles on which they are based are described, and the experiment key performance data are summarized. The launch constraints the helicentric transfer trajectory, and the encounter scenario are analyzed. The Giotto spacecraft major design criteria, spacecraft subsystem and the ground system are described. The problem of hypervelocity dust particle impacts in the innermost part of the coma, the problem of spacecraft survival, and the adverse effects of impact-generated plasma aroung the spacecraft are considered.

Large Alfvén wave power in the plasma sheet boundary layer during the expansion phase of substorms

NASA Astrophysics Data System (ADS)

Keiling, A.; Wygant, J. R.; Cattell, C.; Temerin, M.; Mozer, F. S.; Kletzing, C. A.; Scudder, J.; Russell, C. T.; Lotko, W.; Streltsov, A. V.

2000-10-01

Observations by the Polar satellite of large Poynting flux in the plasma sheet boundary layer at geocentric distances of 4 to 6 RE and between 22 and 3 hrs magnetic local time were correlated with H-bay signatures from ground magnetometer records. We provide evidence that large Poynting fluxes occur during the substorm expansion phase. The Poynting fluxes exceeded 1 ergs/cm²s (125 ergs/cm²s when mapped to 100 km), were dominantly directed toward the ionosphere, and were associated with Alfvén waves. These observations demonstrate the importance of Alfvén wave power as a means of energy transport from the distant magnetotail to the ionosphere during the most dynamic phase of substorms.

Magnetic Field Measurements on the Lunar Surface: Lessons Learned from Apollo and Science Enabled by Future Missions

NASA Astrophysics Data System (ADS)

Chi, P. J.

2017-10-01

We discuss the science to be enabled by new magnetometer measurements on the lunar surface, based on results from Apollo and other lunar missions. Also discussed are approaches to deploying magnetometers on the lunar surface with today's technology.

Spin exchange optical pumping of neon and its applications

NASA Astrophysics Data System (ADS)

Ghosh, Rajat K.

Hyperpolarized noble gases are used in a variety of applications including medical diagnostic lung imaging, tests of fundamental symmetries, spin filters, atomic gyroscopes, and atomic magnetometers. Typically 3He is utilized because large 3He polarizations on the order of 80% can be achieved. This is accomplished by optically pumping an alkali vapour which polarizes a noble gas nucleus via spin exchange optical pumping. One hyperpolarized noble gas application of particular importance is the K-3He co-magnetometer. Here, the alkali atoms optically pump a diamagnetic noble gas. The magnetic holding field for the alkali and noble gas is reduced until both species are brought into hybrid magnetic resonance. The co-magnetometer exhibits many useful attributes which make it ideal for tests of fundamental physics, such as insensitivity to magnetic fields. The co-magnetometer would demonstrate increased sensitivity by replacing 3He with polarized 21Ne gas. Tests of CPT violation using co-magnetometers would be greatly improved if one utilizes polarized 21Ne gas. The sensitivity of the nuclear spin gyroscope is inversely proportional to the gyromagnetic ratio of the noble gas. Switching to neon would instigate an order of magnitude gain in sensitivity over 3He. In order to realize these applications the interaction parameters of 21Ne with alkali metals must be measured. The spin-exchange cross section sigmase, and magnetic field enhancement factor kappa0 are unknown, and have only been theoretically calculated. There are no quantitative predictions of the neon-neon quadrupolar relaxation rate Gammaquad. In this thesis I test the application of a K-3He co-magnetometer as a navigational gyroscope. I discuss the advantages of switching the buffer gas to 21Ne. I discuss the feasibility of utilizing polarized 21Ne for operation in a co-magnetometer, and construct a prototype 21Ne co-magnetometer. I investigate polarizing 21Ne with optical pumping via spin exchange collisions and measure the spin exchange rate coefficient of K and Rb with Ne to be 2.9 x 10-20cm 3/s and 0.81 x 10-19cm3/s. We measure the magnetic field enhancement factor kappa0 to be 30.8 +/- 2.7, and 35.7 +/- 3.7 for the K-Ne, and the Rb-Ne pair. We measure the quadrupolar relaxation coefficient to be 214 +/- 10 Amagat˙s. Furthermore the spin destruction cross section of Rb, and K with 21 Ne is measured to be 1.9 x 10-23cm2 and 1.1 x 10-23cm2.

Electromagnetic Scattering by Multiple Cavities Embedded in the Infinite 2D Ground Plane

DTIC Science & Technology

2014-07-01

Electromagnetic Scattering by Multiple Cavities Embedded in the Infinite 2D Ground Plane Peijun Li 1 and Aihua W. Wood 2 1 Department of...of the electromagnetic wave scattering by multiple open cavities, which are embedded in an infinite two-dimensional ground plane . By introducing a...equation, variational formulation. I. INTRODUCTION A cavity is referred to as a local perturbation of the infinite ground plane . Given the cavity

The EM Earthquake Precursor

NASA Astrophysics Data System (ADS)

Jones, K. B., II; Saxton, P. T.

2013-12-01

Many attempts have been made to determine a sound forecasting method regarding earthquakes and warn the public in turn. Presently, the animal kingdom leads the precursor list alluding to a transmission related source. By applying the animal-based model to an electromagnetic (EM) wave model, various hypotheses were formed, but the most interesting one required the use of a magnetometer with a differing design and geometry. To date, numerous, high-end magnetometers have been in use in close proximity to fault zones for potential earthquake forecasting; however, something is still amiss. The problem still resides with what exactly is forecastable and the investigating direction of EM. After the 1989 Loma Prieta Earthquake, American earthquake investigators predetermined magnetometer use and a minimum earthquake magnitude necessary for EM detection. This action was set in motion, due to the extensive damage incurred and public outrage concerning earthquake forecasting; however, the magnetometers employed, grounded or buried, are completely subject to static and electric fields and have yet to correlate to an identifiable precursor. Secondly, there is neither a networked array for finding any epicentral locations, nor have there been any attempts to find even one. This methodology needs dismissal, because it is overly complicated, subject to continuous change, and provides no response time. As for the minimum magnitude threshold, which was set at M5, this is simply higher than what modern technological advances have gained. Detection can now be achieved at approximately M1, which greatly improves forecasting chances. A propagating precursor has now been detected in both the field and laboratory. Field antenna testing conducted outside the NE Texas town of Timpson in February, 2013, detected three strong EM sources along with numerous weaker signals. The antenna had mobility, and observations were noted for recurrence, duration, and frequency response. Next, two directional techniques were employed, resulting in three mapped, potential epicenters. The remaining, weaker signals presented similar directionality results to more epicentral locations. In addition, the directional results of the Timpson field tests lead to the design and construction of a third prototype antenna. In a laboratory setting, experiments were created to fail igneous rock types within a custom-designed Faraday Cage. An antenna emplaced within the cage detected EM emissions, which were both reproducible and distinct, and the laboratory results paralleled field results. With a viable system and continuous monitoring, a fracture cycle could be established and observed in real-time. Sequentially, field data would be reviewed quickly for assessment; thus, leading to a much improved earthquake forecasting capability. The EM precursor determined by this method may surpass all prior precursor claims, and the general public will finally receive long overdue forecasting.

Magnetometer based on the opto-electronic microwave oscillator

NASA Astrophysics Data System (ADS)

Matsko, Andrey B.; Strekalov, Dmitry; Maleki, Lute

2005-03-01

We present a scheme for an all-optical self-oscillating magnetometer based on the opto-electronic oscillator stabilized with an atomic vapor cell. We demonstrate a proof of the principle with DC magnetic field measurements characterized by 2 × 10-7 G sensitivity and 1-1000 mG dynamic range.

Small Fluxgate Magnetometers: Development and Future Trends in Spain

PubMed Central

Ciudad, David; Díaz-Michelena, Marina; Pérez, Lucas; Aroca, Claudio

2010-01-01

In this paper, we give an overview of the research on fluxgate magnetometers carried out in Spain. In particular we focus in the development of the planar-type instruments. We summarize the fabrication processes and signal processing developments as well as their use in complex systems and space. PMID:22294904

Energy Coupling During the August 2011 Magnetic Storm (Postprint)

DTIC Science & Technology

2014-08-27

of the horizontal cross-track plasma drifts in this study. SSM sensors are triaxial fluxgate magnetometers that are mounted on 0.5m booms on the F15...Special Sensor for Ions Electrons and Scintillations (SSIES)). All of the satellites carry magnetometers (Special Sensor for Magnetic Fields (SSM)) to

Small fluxgate magnetometers: development and future trends in Spain.

PubMed

Ciudad, David; Díaz-Michelena, Marina; Pérez, Lucas; Aroca, Claudio

2010-01-01

In this paper, we give an overview of the research on fluxgate magnetometers carried out in Spain. In particular we focus in the development of the planar-type instruments. We summarize the fabrication processes and signal processing developments as well as their use in complex systems and space.

Astronaut Alan Bean deploys Lunar Surface Magnetometer on lunar surface

NASA Image and Video Library

1969-11-19

Astronaut Alan L. Bean, lunar module pilot, deploys the Lunar Surface Magnetometer (LSM) during the first Apollo 12 extravehicular activity on the Moon. The LSM is a component of the Apollo Lunar Surface Experiments Package (ALSEP). The Lunar Module can be seen in the left background.

Astronaut Alan Bean deploys Lunar Surface Magnetometer on lunar surface

NASA Technical Reports Server (NTRS)

1969-01-01

Astronaut Alan L. Bean, lunar module pilot, deploys the Lunar Surface Magnetometer (LSM) during the first Apollo 12 extravehicular activity on the Moon. The LSM is a component of the Apollo Lunar Surface Experiments Package (ALSEP). The Lunar Module can be seen in the left background.

Miniature Dual-Mode Absolute Scalar Magnetometer Based on the Rubidium Isotope 87Rb

NASA Astrophysics Data System (ADS)

Korth, H.; Strohbehn, K.; Kitching, J.

2016-10-01

Miniaturized absolute scalar magnetometer based on the rubidium isotope 87Rb takes advantage of recent breakthroughs in micro-fabricated atomic devices, has a total mass of 210 g and uses <1 W of power, and maintains a sensitivity of 0.1 nT rms.

Exploring the Use of Alfven Waves in Magnetometer Calibration at Geosynchronous Orbit

NASA Technical Reports Server (NTRS)

Bentley, John; Sheppard, David; RIch, Frederick; Redmon, Robert; Loto'aniu, Paul; Chu, Donald

2016-01-01

An Alfven wave is a type magnetohydrodynamicwave that travels through a conducting fluid under the influence of a magnetic field. Researchers have successfully calculated offset vectors of magnetometers in interplanetary space by optimizing the offset to maximize certain Alfvenic properties of observed waves (Leinweber, Belcher). If suitable Alfven waves can be found in the magnetosphere at geosynchronous altitude then these techniques could be used to augment the overall calibration plan for magnetometers in this region such as on the GOES spacecraft, possibly increasing the time between regular maneuvers. Calibration maneuvers may be undesirable because they disrupt the activities of other instruments. Various algorithms to calculate an offset using Alfven waves were considered. A new variation of the Davis-Smith method was derived because it can be mathematically shown that the Davis-Smith method tolerates filtered data, which expands potential applications. The variant developed was designed to find only the offset in the plane normal to the main field because the overall direction of Earth's magnetic field rarely changes, and theory suggests the Alfvenic disturbances occur transverse to the main field. Other variations of the Davis-Smith method encounter problems with data containing waves that propagate in mostly the same direction. A searching algorithm was then designed to look for periods of time with potential Alfven waves in GOES 15 data based on parameters requiring that disturbances be normal to the main field and not change field magnitude. Final waves for calculation were hand-selected. These waves produced credible two-dimensional offset vectors when input to the Davis-Smith method. Multiple two-dimensional solutions in different planes can be combined to get a measurement of the complete offset. The resulting three dimensional offset did not show sufficient precision over several years to be used as a primary calibration method, but reflected changes in the offset fairly well, suggesting that the method could be helpful in monitoring trends of the offset vector when maneuvers cannot be used.

Lunar physical properties from analysis of magnetometer data

NASA Technical Reports Server (NTRS)

Daily, W. D.

1979-01-01

The electromagnetic properties of the lunar interior are discussed with emphasis on (1) bulk, crustal, and local anomalous conductivity; (2) bulk magnetic permeability measurements, iron abundance estimates, and core size limits; (3) lunar ionosphere and atmosphere; and (4) crustal magnetic remanence: scale size measurements and constraints on remanence origin. Appendices treat the phase relationship between the energetic particle flux modulation and current disc penetrations in the Jovian magnetosphere (Pioneer 10 inbound) theories for the origin of lunar magnetism; electrical conductivity anomalies associated with circular lunar maria; electromagnetic properties of the Moon; Mare Serenitatis conductivity anomaly detected by Apollo 16 and Lunokhod 2 magnetometers; and lunar properties from magnetometer data: effects of data errors.

Assessing and Ensuring GOES-R Magnetometer Accuracy

NASA Technical Reports Server (NTRS)

Kronenwetter, Jeffrey; Carter, Delano R.; Todirita, Monica; Chu, Donald

2016-01-01

The GOES-R magnetometer accuracy requirement is 1.7 nanoteslas (nT). During quiet times (100 nT), accuracy is defined as absolute mean plus 3 sigma. During storms (300 nT), accuracy is defined as absolute mean plus 2 sigma. To achieve this, the sensor itself has better than 1 nT accuracy. Because zero offset and scale factor drift over time, it is also necessary to perform annual calibration maneuvers. To predict performance, we used covariance analysis and attempted to corroborate it with simulations. Although not perfect, the two generally agree and show the expected behaviors. With the annual calibration regimen, these predictions suggest that the magnetometers will meet their accuracy requirements.

Structure of the lunar interior from magnetic field measurements

NASA Technical Reports Server (NTRS)

Dyal, P.; Parkin, C. W.; Daily, W. D.

1976-01-01

A network of lunar surface and orbiting magnetometers was used to obtain measurements of electrical conductivity and magnetic permeability of the lunar interior. An exceptionally large solar transient event, when the moon was in a geomagnetic tail lobe, enabled the most accurate lunar electromagnetic sounding information to date to be obtained. A new analytical technique using a network of two surface magnetometers and a satellite magnetometer superimposes many time series measurements to improve the signal-to-noise ratio and uses both the amplitude and phase information of all three vector components of the magnetic field data. Size constraints on a hypothetical highly conducting lunar core are investigated with the aid of the permeability results.

Relationship between lunar tidal enhancements in the equatorial electrojet and tropospheric eddy heat flux during stratospheric sudden warmings

NASA Astrophysics Data System (ADS)

Siddiqui, T. A.; Yamazaki, Y.; Stolle, C.; Lühr, H.; Matzka, J.

2017-12-01

A number of studies in recent years have reported about the lunar tidal enhancements in the equatorial electrojet (EEJ) from ground- and space-based magnetometer measurements during stratospheric sudden warming (SSW) events. In this study, we make use of the ground magnetometer recordings at Huancayo observatory in Peru for the years 1978 - 2013 to derive a relationship between the lunar tidal enhancements in the EEJ and tropospheric eddy heat fluxes at 100 hPa during the SSW events. Tropospheric eddy heat fluxes are used to quantify the amount of wave activity entering the stratosphere. Anomalously large upward wave activity is known to precede the polar vortex breakdown during SSWs. We make use of the superposed epoch analysis method to determine the temporal relations between lunar tidal enhancements and eddy heat flux anomalies during SSWs, in order to demonstrate the causal relationship between these two phenomena. We also compare the lunar tidal enhancements and eddy heat flux anomalies for vortex split and for vortex displaced SSWs. It is found that larger lunar tidal enhancements are recorded for vortex split events, as compared to vortex displaced events. This confirms earlier observation; larger heat flux anomalies are recorded during vortex split SSW events than the heat flux anomalies during vortex displaced SSW events. Further, the temporal relations of lunar tidal enhancements in the EEJ have been compared separately for both the QBO phases and with the phases of the moon with respect to the central epoch of SSWs by means of the superposed epoch analysis approach. The EEJ lunar tidal enhancements in the east phase of QBO are found to be larger than the lunar tidal enhancements in the west phase of QBO. The phase of moon relative to the central SSW epoch also affects the lunar tidal enhancement in the EEJ. It is found that the lunar tidal enhancements are significantly larger when the day of new or full moon lies near the central SSW epoch, as compared to cases when new or full moon occur further away from the central SSW epoch.

Free-Flying Magnetometer Data System

NASA Technical Reports Server (NTRS)

Blaes, B.; Javadi, H.; Spencer, H.

2000-01-01

The Free-Flying Magnetometer (FFM) is an autonomous "sensorcraft" developed at the Jet Propulsion Laboratory (JPL) for the Enstrophy sounding rocket mission. This mission was a collaborative project between the University of New Hampshire, Cornell University and JPL. The science goal of the mission was the study of current filamentation phenomena in the northern auroral region through multipoint measurements of magnetic field. The technical objective of the mission was the proof of concept of the JPL FFM design and the demonstration of an in-situ multipoint measurement technique employing many free-flying spacecraft. Four FFMs were successfully deployed from a sounding rocket launched from Poker Flats, Alaska on February 11, 1999. These hockey-puck-sized (80 mm diameter, 38 mm. height, 250 gram mass) free flyers each carry a miniature 3-axis flux-gate magnetometer that output +/- 2 V signals corresponding to a +/- 60,000 nT measurement range for each axis. The FFM uses a synchronized four-channel Sigma(Delta) Analog-to-Digital Converter (ADC) having a dynamic range of +/- 2.5V and converting at a rate of 279 samples/second/channel. Three channels are used to digitize the magnetometer signals to 17-bit (1.144 nT/bit) resolution. The fourth ADC channel is multiplexed for system monitoring of four temperature sensors and two battery voltages. The FFM also contains two sun sensors, a laser diode which emits a fan-shaped beam, a miniature S-band transmitter for direct communication to the ground station antennas, an ultra-stable Temperature Compensated Crystal Oscillator (TCXO) clock, an integrated data subsystem implemented in a Field-Programmable Gate Array (FPGA), a 4 Mbit Static Random Access Memory (SRAM) for data storage and Lithium Thionyl Chloride batteries for power. Communicating commands to the FFM prior to deployment is achieved with an infrared (IR) link. The FFM IR receiver responds to 9-bit pulse coded signals that are generated by an IR Light Emitting Diode (LED) in the payload for turning FFM power on or off and placing the FFM in a test mode or flight mode. The IR links are also used to synchronize (zero) the clocks onboard all the FFMs through a reset pulse originating from the payload GPS receiver that is issued when the FFMs are in flight mode. The FPGA based data subsystem manages continuous data collection from the four ADC channels and sun sensors, formatting and storing the data to SRAM, and controlling downlink transmission. The transmitter is powered only after a 2547 frame SRAM buffer has been filled (approx. 5 minutes of data). The data is Viterbi encoded and sent to the S-band transmitter via a First-In-First-Out (FIFO) buffer who's output is clocked at 100 bits/second. After the 26-second transmission, the transmitter is turned off to reduce noise coupling to the sensitive magnetometer. The data subsystem control consists of a master state machine that performs data flow management and is interfaced through a prioritized interrupt scheme to state machines that service the ADC, sun sensors and transmitter FIFO. Continuous data collection prevents the missing of data during transmission and provides implicit time tagging of the data acquired by the ADC because of synchronization with the TCXO clock.

First-Generation Jet Propulsion Laboratory "Hockey-Puck" Free-Flying Magnetometers for Distributed In-Situ Multiprobe Measurement of Current Density Filamentation in the Northern Auroral Zone: Enstrophy Mission

NASA Technical Reports Server (NTRS)

Javadi, H.; Blaes, B.; Boehm, M.; Boykins, K.; Gibbs, J.; Goodman, W.; Lieneweg, U.; Lux, J.; Lynch, K.; Narvaez, P.

2000-01-01

The sub-orbital rocket mission was a collaborative project between the University of New Hampshire, Cornell University, and the Jet Propulsion Laboratory (JPL) to study filamentation phenomena in the northern Auroral zone. The Enstrophy mission test flies the JPL Free-Flying Magnetometer (FFM) concept. The FFM technology development task has been funded by NASA develop miniaturized, low-power, integrated "sensorcrafts". JPL's role was to design, integrate, test, and deliver four FFMs for deployment from the sounding rocket, allowing a unique determination of curl-B. This provides a direct measurement of magnetic-field-aligned current density along the rocket trajectory. A miniaturized three-axis fluxgate magnetometer was integrated with a 4-channel 22-bit sigma-delta Analog to Digital Converter (ADC), four temperature sensors, digital control electronics, seven (Li-SOCl2) batteries, two (4 deg x 170 deg field of view) sun-sensors, a fan-shaped-beam laser diode beacon, a (16 MHz) stable Temperature Compensated Crystal Oscillator (TCXO) clock, Radio Frequency (RF) communication subsystem, and an antenna for approximately 15 minutes of operation where data was collected continuously and transmitted in three (3) bursts (approximately 26 seconds each) to ground station antennas at Poker Flat, Alaska. FFMs were stowed within two trays onboard the rocket during the rocket launch and were released simultaneously using the spinning action of the rocket at approximately 300 km altitude (approximately 100 sec. into the flight). FFMs were deployed with spin rate of approximately 17 Hz and approximately 3 m/sec linear velocity with respect to the rocket. For testing purposes while the rocket was in the launch pad and during flight prior to release of FFMs from the rocket, commands (such as "power on", "test", "flight", "power off', and clock "Reset" signal) were transmitted via a infrared Light Emitting Diode to an infrared detector in the FFM. Special attention was paid to low magnetic signature electronic design and choice of materials in packaging. The miniaturized fluxgate magnetometers had a range of 1-60000 nT with 0.1% full-scale linearity. The frequency range of interest for magnetic measurement was 10 mHz - 50 Hz. Digital data from the magnetometer's three axes were placed in a 4MB Static Random Access Memory (SRAM) in data packages (frames) formatted together with time tags and frame ID. After a specified time was elapsed, the data were Viterbi encoded and transmitted at a rate of 100 kbps (BPSK). Each of the four FFMs transmitted at different frequency. These carrier frequencies were in the range of 2200-2300 MHz. The antenna was a single patch on a high dielectric constant substrate covering one end-plate of the hockey-puck-sized unit. The local clocks aboard the FFMs were reset at the start of the mission and stayed synchronized within 3 msec during the mission. Position of each FFM with respect to the rocket is calculated by the knowledge of its release velocity (measured at exit point of the FFM launcher tract) providing an accuracy of 1 m over the maximum range of 3 km. Spatial and temporal nature of observants can be separated to within 3 m in space or 3 msec time interval.

Multifuctional integrated sensors (MFISES).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Homeijer, Brian D.; Roozeboom, Clifton

2015-10-01

Many emerging IoT applications require sensing of multiple physical and environmental parameters for: completeness of information, measurement validation, unexpected demands, improved performance. For example, a typical outdoor weather station measures temperature, humidity, barometric pressure, light intensity, rainfall, wind speed and direction. Existing sensor technologies do not directly address the demand for cost, size, and power reduction in multi-paramater sensing applications. Industry sensor manufacturers have developed integrated sensor systems for inertial measurements that combine accelerometers, gyroscopes, and magnetometers, but do not address environmental sensing functionality. In existing research literature, a technology gap exists between the functionality of MEMS sensors and themore » real world applications of the sensors systems.« less

OM300 Direction Drilling Module

DOE Data Explorer

MacGugan, Doug

2013-08-22

OM300 – Geothermal Direction Drilling Navigation Tool: Design and produce a prototype directional drilling navigation tool capable of high temperature operation in geothermal drilling Accuracies of 0.1° Inclination and Tool Face, 0.5° Azimuth Environmental Ruggedness typical of existing oil/gas drilling Multiple Selectable Sensor Ranges High accuracy for navigation, low bandwidth High G-range & bandwidth for Stick-Slip and Chirp detection Selectable serial data communications Reduce cost of drilling in high temperature Geothermal reservoirs Innovative aspects of project Honeywell MEMS* Vibrating Beam Accelerometers (VBA) APS Flux-gate Magnetometers Honeywell Silicon-On-Insulator (SOI) High-temperature electronics Rugged High-temperature capable package and assembly process

Plasma Conditions During the Galaxy 15 Anomaly and the Possibility of ESD from Subsurface Charging (Postprint)

DTIC Science & Technology

2011-09-15

LANL) moments calculations27, with changes to account for the different instruments and the presence of a magnetometer on GOES. First, the pitch...angle for each telescope was determined using the magnetic field components from a co-manifested triaxial fluxgate magnetometer26. The velocity

Improved Magnetic STAR Methods for Real-Time, Point-by-Point Localization of Unexploded Ordnance and Buried Mines

DTIC Science & Technology

2008-09-01

of magnetic UXO. The prototype STAR Sensor comprises: a) A cubic array of eight fluxgate magnetometers . b) A 24-channel data acquisition/signal...array (shaded boxes) of eight low noise Triaxial Fluxgate Magnetometers (TFM) develops 24 channels of vector B- field data. Processor hardware

MetalMapper: A Multi-Sensor TEM System for UXO Detection and Classification

DTIC Science & Technology

2011-04-01

fluxgate magnetometer that provides reference heading to magnetic north. DeploymentCThe MM can be deployed either as a man-powered cart or as a...is a live site. Preliminary investigations included a magnetometer transect survey and an EMI survey over a larger area to assist in selecting a

A new algorithm for attitude-independent magnetometer calibration

NASA Technical Reports Server (NTRS)

Alonso, Roberto; Shuster, Malcolm D.

1994-01-01

A new algorithm is developed for inflight magnetometer bias determination without knowledge of the attitude. This algorithm combines the fast convergence of a heuristic algorithm currently in use with the correct treatment of the statistics and without discarding data. The algorithm performance is examined using simulated data and compared with previous algorithms.

In-Flight Calibration Processes for the MMS Fluxgate Magnetometers

NASA Technical Reports Server (NTRS)

Bromund, K. R.; Leinweber, H. K.; Plaschke, F.; Strangeway, R. J.; Magnes, W.; Fischer, D.; Nakamura, R.; Anderson, B. J.; Russell, C. T.; Baumjohann, W.;

Non-invasive detection of animal nerve impulses with an atomic magnetometer operating near quantum limited sensitivity

PubMed Central

Jensen, Kasper; Budvytyte, Rima; Thomas, Rodrigo A.; Wang, Tian; Fuchs, Annette M.; Balabas, Mikhail V.; Vasilakis, Georgios; Mosgaard, Lars D.; Stærkind, Hans C.; Müller, Jörg H.; Heimburg, Thomas; Olesen, Søren-Peter; Polzik, Eugene S.

2016-01-01

Magnetic fields generated by human and animal organs, such as the heart, brain and nervous system carry information useful for biological and medical purposes. These magnetic fields are most commonly detected using cryogenically-cooled superconducting magnetometers. Here we present the first detection of action potentials from an animal nerve using an optical atomic magnetometer. Using an optimal design we are able to achieve the sensitivity dominated by the quantum shot noise of light and quantum projection noise of atomic spins. Such sensitivity allows us to measure the nerve impulse with a miniature room-temperature sensor which is a critical advantage for biomedical applications. Positioning the sensor at a distance of a few millimeters from the nerve, corresponding to the distance between the skin and nerves in biological studies, we detect the magnetic field generated by an action potential of a frog sciatic nerve. From the magnetic field measurements we determine the activity of the nerve and the temporal shape of the nerve impulse. This work opens new ways towards implementing optical magnetometers as practical devices for medical diagnostics. PMID:27417378

Preliminary calibration plan for the Advanced Particles and Field Observatory (APAFO) magnetometer experiment

NASA Technical Reports Server (NTRS)

Voorhies, C. V.; Langel, R. A.; Slavin, J.; Lancaster, E. R.; Jones, S.

1991-01-01

Prelaunch and postlaunch calibration plans for the APAFO magnetometer experiment are presented. A study of tradeoffs between boom length and spacecraft field is described; the results are summarized. The prelaunch plan includes: calibration of the Vector Fluxgate Magnetometer (VFM), Star Sensors, and Scalar Helium Magnetometer (SHM); optical bench integration; and acquisition of basic spacecraft field data. Postlaunch calibration has two phases. In phase one, SHM data are used to calibrate the VFM, total vector magnetic field data are used to calibrate a physical model of the spacecraft field, and both calibrations are refined by iteration. In phase two, corrected vector data are transformed into geocentric coordinates, previously undetected spacecraft fields are isolated, and initial geomagnetic field models are computed. Provided the SHM is accurate to the required 1.0 nT and can be used to calibrate the VFM to the required 3.0- nT accuracy, the tradeoff study indicates that a 12 m boom and a spacecraft field model uncertainty of 5 percent together allow the 1.0 nT spacecraft field error requirement to be met.

Modeling Geomagnetically Induced Currents From Magnetometer Measurements: Spatial Scale Assessed With Reference Measurements

NASA Astrophysics Data System (ADS)

Butala, Mark D.; Kazerooni, Maryam; Makela, Jonathan J.; Kamalabadi, Farzad; Gannon, Jennifer L.; Zhu, Hao; Overbye, Thomas J.

2017-10-01

Solar-driven disturbances generate geomagnetically induced currents (GICs) that can result in power grid instability and, in the most extreme cases, even failure. Magnetometers provide direct measurements of the geomagnetic disturbance (GMD) effect on the surface magnetic field and GIC response can be determined from the power grid topology and engineering parameters. This paper considers this chain of models: transforming surface magnetic field disturbance to induced surface electric field through an electromagnetic transfer function and, then, induced surface electric field to GIC using the PowerWorld simulator to model a realistic power grid topology. Comparisons are made to transformer neutral current reference measurements provided by the American Transmission Company. Three GMD intervals are studied, with the Kp index reaching 8- on 2 October 2013, 7 on 1 June 2013, and 6- on 9 October 2013. Ultimately, modeled to measured GIC correlations are analyzed as a function of magnetometer to GIC sensor distance. Results indicate that modeling fidelity during the three studied GMD intervals is strongly dependent on both magnetometer to substation transformer baseline distance and GMD intensity.

Optically pumped quantum magnetometer with combined advantages of M X and M Z devices

NASA Astrophysics Data System (ADS)

Vershovskii, A. K.; Dmitriev, S. P.; Pazgalev, A. S.

2013-10-01

A scheme of the magnetometer that simultaneously employs M X and M R magnetic resonance signals with the latter signal related to the radial component of the rotating atomic magnetic moment is proposed and tested. With respect to the shape, dynamic characteristics, and metrological parameters, the M R signal is similar to the M X signal that is widely used in magnetometry but the former signal can be detected simultaneously with the M X signal using a common radio optical scheme. The proposed device represents a fast M X magnetometer with the phase in the feedback loop that is controlled by a slow precise M R magnetometer implemented using the same atoms. The device that can be based on a conventional M X sensor simultaneously exhibits a relatively short response time (τ ≤ 0.1 s) and the accuracy that is approximately equal to the resolution of the quantum M X discriminator at times of 10-100 s. The scheme is experimentally tested, and the statistic estimate of reproducibility is (1.2 ± 1.1) pT.

The MAGIC of CINEMA: first in-flight science results from a miniaturised anisotropic magnetoresistive magnetometer

NASA Astrophysics Data System (ADS)

Archer, M. O.; Horbury, T. S.; Brown, P.; Eastwood, J. P.; Oddy, T. M.; Whiteside, B. J.; Sample, J. G.

2015-06-01

We present the first in-flight results from a novel miniaturised anisotropic magnetoresistive space magnetometer, MAGIC (MAGnetometer from Imperial College), aboard the first CINEMA (CubeSat for Ions, Neutrals, Electrons and MAgnetic fields) spacecraft in low Earth orbit. An attitude-independent calibration technique is detailed using the International Geomagnetic Reference Field (IGRF), which is temperature dependent in the case of the outboard sensor. We show that the sensors accurately measure the expected absolute field to within 2% in attitude mode and 1% in science mode. Using a simple method we are able to estimate the spacecraft's attitude using the magnetometer only, thus characterising CINEMA's spin, precession and nutation. Finally, we show that the outboard sensor is capable of detecting transient physical signals with amplitudes of ~ 20-60 nT. These include field-aligned currents at the auroral oval, qualitatively similar to previous observations, which agree in location with measurements from the DMSP (Defense Meteorological Satellite Program) and POES (Polar-orbiting Operational Environmental Satellites) spacecraft. Thus, we demonstrate and discuss the potential science capabilities of the MAGIC instrument onboard a CubeSat platform.

Numerical study of ultra-low field nuclear magnetic resonance relaxometry utilizing a single axis magnetometer for signal detection.

PubMed

Vogel, Michael W; Vegh, Viktor; Reutens, David C

2013-05-01

This paper investigates optimal placement of a localized single-axis magnetometer for ultralow field (ULF) relaxometry in view of various sample shapes and sizes. The authors used finite element method for the numerical analysis to determine the sample magnetic field environment and evaluate the optimal location of the single-axis magnetometer. Given the different samples, the authors analysed the magnetic field distribution around the sample and determined the optimal orientation and possible positions of the sensor to maximize signal strength, that is, the power of the free induction decay. The authors demonstrate that a glass vial with flat bottom and 10 ml volume is the best structure to achieve the highest signal out of samples studied. This paper demonstrates the importance of taking into account the combined effects of sensor configuration and sample parameters for signal generation prior to designing and constructing ULF systems with a single-axis magnetometer. Through numerical simulations the authors were able to optimize structural parameters, such as sample shape and size, sensor orientation and location, to maximize the measured signal in ultralow field relaxometry.

Non-invasive detection of animal nerve impulses with an atomic magnetometer operating near quantum limited sensitivity

NASA Astrophysics Data System (ADS)

Jensen, Kasper; Budvytyte, Rima; Thomas, Rodrigo A.; Wang, Tian; Fuchs, Annette M.; Balabas, Mikhail V.; Vasilakis, Georgios; Mosgaard, Lars D.; Stærkind, Hans C.; Müller, Jörg H.; Heimburg, Thomas; Olesen, Søren-Peter; Polzik, Eugene S.

2016-07-01

Magnetic fields generated by human and animal organs, such as the heart, brain and nervous system carry information useful for biological and medical purposes. These magnetic fields are most commonly detected using cryogenically-cooled superconducting magnetometers. Here we present the first detection of action potentials from an animal nerve using an optical atomic magnetometer. Using an optimal design we are able to achieve the sensitivity dominated by the quantum shot noise of light and quantum projection noise of atomic spins. Such sensitivity allows us to measure the nerve impulse with a miniature room-temperature sensor which is a critical advantage for biomedical applications. Positioning the sensor at a distance of a few millimeters from the nerve, corresponding to the distance between the skin and nerves in biological studies, we detect the magnetic field generated by an action potential of a frog sciatic nerve. From the magnetic field measurements we determine the activity of the nerve and the temporal shape of the nerve impulse. This work opens new ways towards implementing optical magnetometers as practical devices for medical diagnostics.

Interball-1 and MIR orbital station coordinated magnetic field and energetic particles measurements

NASA Astrophysics Data System (ADS)

Klimov, S. I.; Grushin, V. A.; Lissakov, Yu. V.; Nozdrachev, M. N.; Petrukovich, A. A.; Grachev, E. A.; Grigoryan, O. R.; Lysakov, D. S.; Schwingenschuh, K.; Auster, H. U.; Fornacon, K.-H.; Rustenbach, J.; Korepanov, V. E.; Juchniewicz, J.; Afanasjev, Yu. V.; Kudela, K.

Magnetic field measurements in solar wind and outer magnetosphere onboard the INTERBALL-1 spacecraft were performed by the following magnetometers: MIF-M magnetometer with both DC sensor (BPP) having 0.2 nT threshold sensitivity at DC and 5 pT at 1 Hz and AC sensor (DM2) with the sensitivity about 0.2 nT at 1 Hz and 0.4 pT at 100 Hz; FGM-I DC magnetometer with threshold sensitivity of 5 pT at 1 Hz; FM-31 DC magnetometer with two sensors having 0.1 nT (sensor MI) and 1.0 nT (sensor M2) threshold sensitivity. During INTERBALL-1 operation the ionosphere experiment SPRUT-VI onboard the MIR station was performed from 06/13-08/26/1999. The measurements of DC magnetic field, electron and ion fluxes at energies between 50 keV-2.5 MeV and 50 keV-30 MeV were made. The SPRUT-MAG digital magnetometer for this experiment is based on the one developed for the ESA Rosetta Lander device ROMAP which threshold sensitivity was about 5 pT/(Hz) 1/2 at 1 Hz. This paper discusses the possibility of signals processing with the aim to separate the artificial (technical, connected with the MIR onboard system operation) and natural origin signals as well as to estimate the level of ULF/ELF magnetic field disturbances and particle flows bursts.

Noise Reduction of 1sec Geomagnetic Observatory Data without Information Loss

NASA Astrophysics Data System (ADS)

Brunke, Heinz-Peter; Korte, Monika; Rudolf, Widmer-Schnidrig

2017-04-01

Traditional fluxgate magnetometers used at geomagnetic observatories are optimized towards long-term stability. Typically, such instruments can only resolve background geomagnetic field variations up to a frequency of approximately 0.04 Hz and are limited by instrumental self-noise above this frequency. However, recently the demand for low noise 1 Hz observatory data has increased. IAGA has defined a standard for definitive 1sec data. Induction coils have low noise at these high frequencies, but lack long-term stability. We present a method to numerically combine the data from a three axis induction coil system with a typical low-drift observatory fluxgate magnetometer. The resulting data set has a reduced noise level above 0.04 Hz while maintaining the long term stability of the fluxgate magnetometer. Numerically we fit a spline to the fluxgate data. But in contrast to such a low pass filtering process, our method reduces the noise level at high frequencies without any loss of information. In order to experimentally confirm our result, we compared it to a very low noise scalar magnetometer: an optically pumped potassium magnetometer. In the frequency band from [0.03Hz to 0.5Hz] we found an rms-noise reduction from 80pT for the unprocessed fluxgate data to about 25pT for the processed data. We show how our method improves geomagnetic 1 sec observatory data for, e.g., the study of magnetospheric pulsations and EMIC waves.

Co-Investigator Proposal for Enstrophy - - Filamentation of Auroral Currents

NASA Technical Reports Server (NTRS)

Kintner, Paul M.

2000-01-01

Cornell University provided three instruments for the Enstrophy experiment: an electric field meter, a plasma wave receiver, and a magnetometer for measuring FAC. The electric field meter consisted of a 6 m Weitzmann boom system with analog signal processing and 12 bit ADC, which yielded one electric field component instantaneously and a two dimensional electric field every half spin. The plasma wave receiver used the same sensing system with the addition of pre-amplifiers in the spheres to sense plasma waves up to and including the electron Langmuir frequency. Signal processing employed a variety of continuous and snap shot techniques depending on the frequency range and band width. The science magnetometer provided by Cornell University was a Billingsly design fluxgate previously used on spacecraft missions but without radiation hardening. The magnetometer was mounted on a one meter, stiff aluminum "flop-down" boom. The Enstrophy payload was launched on february 11, 1999. Because of a design flaw in the event timers, the magnetometer boom was deployed before the payload despun. As a result the magnetometer separated mechanically from the boom but maintained electrical connection. This was confirmed by the calculation of the scalar magnetic field from all three vector components of the magnetic field. However, the individual vector values had no scientific value. The electric field and plasma wave instrumentation worked as designed. The data from these instruments was provided to the University of New Hampshire and to the Principal Investigator, as proposed.

Excitation of the ionospheric Alfvén resonator from the ground: Theory and experiments

NASA Astrophysics Data System (ADS)

Streltsov, A. V.; Chang, C.-L.; Labenski, J.; Milikh, G.; Vartanyan, A.; Snyder, A. L.

2011-10-01

We report results from numerical and experimental studies of the excitation of ULF shear Alfvén waves inside the ionospheric Alfvén resonator (IAR) by heating the ionosphere with powerful HF waves launched from the High Frequency Active Auroral Research Program (HAARP) facility in Alaska. Numerical simulations of the two-fluid MHD model describing IAR in a dipole magnetic field geometry with plasma parameters taken from the observations at HAARP during the October-November 2010 experimental campaign reveal that the IAR quality is higher during nighttime conditions, when the ionospheric conductivity is very low. Simulations also reveal that the resonance wave cannot be identified from the magnetic measurements on the ground or at an altitude above 600 km because the magnetic field in this wave has nodes on both ends of the resonator, and the best way to detect IAR modes is by measuring the electric field on low Earth orbit satellites. These theoretical predictions are in good, quantitative agreement with results from observations: In particular, (1) observations from the ground-based magnetometer at the HAARP site demonstrate no significant difference in the amplitudes of the magnetic field generated by HAARP in the frequency range from 0 to 5 Hz, and (2) the DEMETER satellite detected the electric field of the IAR first harmonic at an altitude of 670 km above HAARP during the heating experiment.

Qualitative analysis of the magnetic data collected by the Embrace MagNet in comparison to absolute measurements made by Intermagnet in Vassouras-RJ

NASA Astrophysics Data System (ADS)

Chen, Sony Su; Moro, Juliano; Araujo Resende, Laysa Cristina; Denardini, Clezio Marcos

2016-07-01

The Embrace Magnetometer Network (Embrace MagNet) is a network of three-axis fluxgate magnetometers using single bars with high level of magnetic saturation, covered with two copper coils, one for the excitation and the second for sensing the external field. It is planned to cover most of the Easter Southern American longitudinal sector in order to fulfill the gap for magnetic measurement available on-line. The availability of fast internet, reliable energy supply and easy access were the key point for deciding the location of the magnetometer stations of the network. Up to now, the main characteristic of this network is the severe sensibility matching process among all the magnetometers composing it. Now, in order to validate the magnetic data collected by the elements of the Embrace MagNet in comparison to absolute measurements, we performed a study about the correlation between the data collected by the fluxgate magnetometer provided by Embrace MagNet and an absolute magnetometer installed by Intermagnet in the same observatory. For this study, we have used data collected in Vassouras-RJ, in Brazil, covering the period from June to December 2015. The analysis consist of: (a) selecting the 5 quietest days and the 5 most disturbed days of each month based on the Kp index; (b) deducing the local midnight value from the data collected by both instruments; (c) correlating the data collected by the variometer with the absolute measurement day-by-day; (d) grouping the results as Winter (June, July, and August), Equinox (September and October) and Summer (November and December); (e) obtaining the linear correlations factor for each group. The averaged correlation factors and the daily variations of the magnetic data are presented and discussed in terms of the magnetic activity and the season variation.

Characterization of the head-twitch response induced by hallucinogens in mice: detection of the behavior based on the dynamics of head movement.

PubMed

Halberstadt, Adam L; Geyer, Mark A

2013-06-01

The head-twitch response (HTR) is a rapid side-to-side rotational head movement that occurs in rats and mice after administration of serotonergic hallucinogens and other 5-HT2A agonists. The HTR is widely used as a behavioral assay for 5-HT2A activation and to probe for interactions between the 5-HT2A receptor and other transmitter systems. High-speed video recordings were used to analyze the head movement that occurs during head twitches in C57BL/6J mice. Experiments were also conducted in C57BL/6J mice to determine whether a head-mounted magnet and a magnetometer coil could be used to detect the HTR induced by serotonergic hallucinations based on the dynamics of the response. Head movement during the HTR was highly rhythmic and occurred within a specific frequency range (mean head movement frequency of 90.3 Hz). Head twitches produced wave-like oscillations of magnetometer coil voltage that matched the frequency of head movement during the response. The magnetometer coil detected the HTR induced by the serotonergic hallucinogens 2,5-dimethoxy-4-iodoamphetamine (DOI; 0.25, 0.5, and 1.0 mg/kg, i.p.) and lysergic acid diethylamide (LSD; 0.05, 0.1, 0.2, and 0.4 mg/kg, i.p.) with extremely high sensitivity and specificity. Magnetometer coil recordings demonstrated that the non-hallucinogenic compounds (+)-amphetamine (2.5 and 5.0 mg/kg, i.p.) and lisuride (0.8, 1.6, and 3.2 mg/kg, i.p.) did not induce the HTR. These studies confirm that a magnetometer coil can be used to detect the HTR induced by hallucinogens. The use of magnetometer-based HTR detection provides a high-throughput, semi-automated assay for this behavior, and offers several advantages over traditional assessment methods.

Characterization of the head-twitch response induced by hallucinogens in mice: detection of the behavior based on the dynamics of head movement

PubMed Central

Halberstadt, Adam L.; Geyer, Mark A.

2013-01-01

Rationale The head-twitch response (HTR) is a rapid side-to-side rotational head movement that occurs in rats and mice after administration of serotonergic hallucinogens and other 5-HT2A agonists. The HTR is widely used as a behavioral assay for 5-HT2A activation and to probe for interactions between the 5-HT2A receptor and other transmitter systems. Objective High-speed video recordings were used to analyze the head movement that occurs during head twitches in C57BL/6J mice. Experiments were also conducted in C57BL/6J mice to determine whether a head-mounted magnet and a magnetometer coil could be used to detect the HTR induced by serotonergic hallucinations based on the dynamics of the response. Results Head movement during the HTR was highly rhythmic and occurred within a specific frequency range (mean reciprocation frequency of 90.3 Hz). Head twitches produced wave-like oscillations of magnetometer coil voltage that matched the frequency of head movement during the response. The magnetometer coil detected the HTR induced by the serotonergic hallucinogens 2,5-dimethoxy-4-iodoamphetamine (DOI; 0.25, 0.5, and 1.0 mg/kg, IP) and lysergic acid diethylamide (LSD; 0.05, 0.1, 0.2, and 0.4 mg/kg, IP) with extremely high sensitivity and specificity. Magnetometer coil recordings demonstrated that the non-hallucinogenic compounds (+)-amphetamine (2.5 and 5.0 mg/kg, IP) and lisuride (0.8, 1.6, and 3.2 mg/kg, IP) did not induce the HTR. Conclusions These studies confirm that a magnetometer coil can be used to detect the HTR induced by hallucinogens. The use of magnetometer-based HTR detection provides a high-throughput, semi-automated assay for this behavior, and offers several advantages over traditional assessment methods. PMID:23407781

Instruments for Planetary Exploration with CubeSats and SmallSats

NASA Astrophysics Data System (ADS)

Raymond, Carol; Jaumann, Ralf; Vane, Gregg; Baker, John; Castillo-Rogez, Julie; Yano, Hajime

2016-07-01

Planetary sensors and instruments are undergoing a revolutionary transformation as solid-state electronics and advanced detectors allow drastic reductions in size, mass and power relative to instruments flown in the past. Given their reduced resource needs, these capable new systems are potentially compatible with use on smallsats. New built-in processing techniques further enable increased science return in constrained resource environments. In the summer of 2014 an international group of scientists, engineers, and technologists started a study to define investigations to be carried out by nano-spacecraft, and instruments that would enable breakthrough science from these small platforms were identified. The possibilities include passive remote sensing instruments such as imagers, spectrometers, magnetometers, dust analyzers; active instruments such as radar, lidar, laser-induced breakdown spectroscopy (LIBS), muonography, projectiles; and landed packages and in-situ probes such as instrumented penetrators, seismometers, and in-situ sample analysis packages. Many of the passive and active instruments could be used in-situ for very high-resolution measurements over limited areas. Smallsats lend themselves to observing strategies that allow dense spatial and temporal sampling using multiple flight system elements, covering a range of observing conditions, and multi-scale measurements with concurrent surface and remote observations. The lower cost of smallsats allows visiting a large range of targets and provides an architecture for cooperating distributed networks of sensors. The current state-of-the-art in smallsat payloads includes instrument suites on the Philae lander (Rosetta), and the MINERVA-II rovers and MASCOT on Hayabusa-2. Many Cubesat form factor instruments are either built or in development, including impactors and penetrators, and several new technologies are making their debut in the smallsat arena. The Philae payload included the CONSERT active radar experiment, MUPUS hammer and heat flow probes, magnetometer, ROLIS cameras and ROSINA mass spectrometer. MASCOT carries MicrOmega (NIR spectrometer), magnetometer, camera, and radiometer. The INSPIRE Cubesat mission carries a 1/2U Vector Helium Magnetometer. An intelligent camera maturing for flight in 2018 on the NEA Scout Cubesat mission promises to deliver a low-cost dual-use navigation and science capability at Cubesat scale. Cubesat versions of VIS-IR imaging spectrometers, neutron and gamma-ray spectrometers, mass spectrometers, tunable laser diode spectrometer and active radar are under development. Acknowledgements: This study is sponsored by the International Academy of Astronautics (IAA). Part of this work is being carried out at the Jet Propulsion Lab, California Institute of Technology, under contract to NASA.

The Juno Magnetic Field Investigation

NASA Astrophysics Data System (ADS)

Connerney, J. E. P.; Benn, M.; Bjarno, J. B.; Denver, T.; Espley, J.; Jorgensen, J. L.; Jorgensen, P. S.; Lawton, P.; Malinnikova, A.; Merayo, J. M.; Murphy, S.; Odom, J.; Oliversen, R.; Schnurr, R.; Sheppard, D.; Smith, E. J.

2017-11-01

The Juno Magnetic Field investigation (MAG) characterizes Jupiter's planetary magnetic field and magnetosphere, providing the first globally distributed and proximate measurements of the magnetic field of Jupiter. The magnetic field instrumentation consists of two independent magnetometer sensor suites, each consisting of a tri-axial Fluxgate Magnetometer (FGM) sensor and a pair of co-located imaging sensors mounted on an ultra-stable optical bench. The imaging system sensors are part of a subsystem that provides accurate attitude information (to ˜20 arcsec on a spinning spacecraft) near the point of measurement of the magnetic field. The two sensor suites are accommodated at 10 and 12 m from the body of the spacecraft on a 4 m long magnetometer boom affixed to the outer end of one of 's three solar array assemblies. The magnetometer sensors are controlled by independent and functionally identical electronics boards within the magnetometer electronics package mounted inside Juno's massive radiation shielded vault. The imaging sensors are controlled by a fully hardware redundant electronics package also mounted within the radiation vault. Each magnetometer sensor measures the vector magnetic field with 100 ppm absolute vector accuracy over a wide dynamic range (to 16 Gauss = 1.6 × 106 nT per axis) with a resolution of ˜0.05 nT in the most sensitive dynamic range (±1600 nT per axis). Both magnetometers sample the magnetic field simultaneously at an intrinsic sample rate of 64 vector samples per second. The magnetic field instrumentation may be reconfigured in flight to meet unanticipated needs and is fully hardware redundant. The attitude determination system compares images with an on-board star catalog to provide attitude solutions (quaternions) at a rate of up to 4 solutions per second, and may be configured to acquire images of selected targets for science and engineering analysis. The system tracks and catalogs objects that pass through the imager field of view and also provides a continuous record of radiation exposure. A spacecraft magnetic control program was implemented to provide a magnetically clean environment for the magnetic sensors, and residual spacecraft fields and/or sensor offsets are monitored in flight taking advantage of Juno's spin (nominally 2 rpm) to separate environmental fields from those that rotate with the spacecraft.

The Juno Magnetic Field Investigation

NASA Technical Reports Server (NTRS)

Connerney, J. E. P.; Benna, M.; Bjarno, J. B.; Denver, T.; Espley, J.; Jorgensen, J. L.; Jorgensen, P. S.; Lawton, P.; Malinnikova, A.; Merayo, J. M.;

Development of Next-Generation Borehole Magnetometer and Its Potential Application in Constraining the Magnetic Declination of Oman Samail Ophiolite at ICDP Drill Sites

NASA Astrophysics Data System (ADS)

Lee, S. M.; Parq, J. H.; Kim, H.; Moe, K.; Lee, C. S.; Kanamatsu, T.; Kim, K. J.; Bahk, K. S.

2017-12-01

Determining the azimuthal orientation of core samples obtained from deep drilling is extremely difficult because the core itself could have rotated during drilling operations. Several indirect methods have been devised to address this issue, but have certain limitations. Thus it is still a challenge to determine the azimuthal orientation consistently over the entire length of the hole. Provided that the recovery rate is high and thus all the other magnetic properties such as magnetization intensity and inclination are measured from the recovered cores, one possible method for ascertaining magnetic declination information is to measure the magnetic field inside the empty borehole and invert for the best fitting declination. However, there are two major problems: one is that present-day borehole magnetometers are not precise enough to resolve changes in direction of magnetization, and the other is that in most rock drilling experiments the rate of recovery is low. To overcome the first major problem which is technical, scientists from Korea and Japan jointly conducted the development for the next-generation borehole magnetometer, namely 3GBM (3rd Generation Borehole Magnetometer). The borehole magnetometer which uses fiber-optic laser gyro promises to provide accurate information on not only the magnetic field itself but also the orientation of the instrument inside the borehole. Our goal is to deploy this borehole magnetometer in the ICDP Oman Drilling Project Phase 2 drilling experiment early 2018. The site may be suitable for the investigation because, as recent Phase 1 of the Oman Samail Ophiolite drilling has demonstrated, the recovery rate was very high. Also the post-drilling measurements onboard DV Chikyu have shown that much of the recovered samples has moderate magnetization intensity on the order of 0.1 and 1 A/m. Here, we present the results of numerical simulation of magnetic field inside the borehole using finite element method to show that magnetic declination may be obtained systematically from the top to the bottom of the holes. The results will help us to fine tune the magnetometer before the actual deployment. It will also be useful in interpreting the obtained results together with resistivity images from conventional wireline logging and post-drilling paleomagnetic lab measurements results.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Young Jin

The PowerPoint presentation focused on research goals, specific information about the atomic magnetometer, response and resolution factors of the SERF magnetometer, FC+AM systems, tests of field transfer and resolution on FC, gradient cancellation, testing of AM performance, ideas for a multi-channel AM, including preliminary sensitivity testing, and a description of a 6 channel DAQ system. A few ideas for future work ended the presentation.

MAGNETOMETER - TRI-AXIS SENSOR UNIT - GEMINI-TITAN (GT)-12 EXPERIMENT MSC-3 (M405) - MSC

NASA Image and Video Library

1966-10-01

S66-09379 (1 Oct. 1966) --- Tri-Axis Magnetometer-Sensor Unit mounted on telescoping boom. Cable connects Sensor Unit with Electronics Unit mounted on retrograde beam in retrograde adapter section. Objective of experiment is to monitor the direction and amplitude of Earth's magnetic field (Gemini-12). Photo credit: NASA

View of the Lunar Portable Magnetometer on the LRV photographed during EVA

NASA Technical Reports Server (NTRS)

1972-01-01

View of the Lunar Portable Magnetometer mounted on the Lunar Roving Vehicle (LRV) which was parked at Station 2 on the Descartes lunar landing site. It was photographed by the Apollo 16 crew during their second extravehicular activity (EVA-2). Note the shadow of the astronaut taking the photograph in the left foreground.

Magnetometer Based on the Opto-Electronic Oscillator

NASA Technical Reports Server (NTRS)

Matsko, Andrey B.; Strekalov, Dmitry; Maleki, Lute

2005-01-01

We theoretically propose and discuss properties of two schemes of an all-optical self-oscillating magnetometer based on an opto-electronic oscillator stabilized with an atomic vapor cell. Proof of the principle DC magnetic field measurements characterized with 2 x 10(exp -7) G sensitivity and 1 - 1000 mG dynamic range in one of the schemes are demonstrated.

An Arduino-Based Magnetometer

ERIC Educational Resources Information Center

McCaughey, Mike

2017-01-01

An Arduino-based system with a triple axis magnetometer chip may be used to plot both the strength and direction of the magnetic field of a magnet directly on a sheet of paper. Before taking measurements, it is necessary either to correct for or to eliminate soft and hard iron effects. The same sensor may be used to determine the presence of soft…

Properties of the moon and its environment from lunar magnetometer measurements

NASA Technical Reports Server (NTRS)

Parkin, C. W.

1976-01-01

Lunar analysis of data from a total of nine lunar magnetometers is described. Results obtained concerning electromagnetic, compositional, and structural properties of the lunar interior are discussed. Specific topics covered include: lunar magnetic permeability and iron abundance; limits on a highly conducting lunar core; lunar electrical conductivity; and internal structure inferred from conductivity and permeability results.

The EMBRACE Magnetometer Network in South America: Network Description and Firsts Results

NASA Astrophysics Data System (ADS)

Denardini, Clezio Marcos

We present the new EMBRACE Magnetometer Network in South America, which so far is planned to cover most of the Easter Southern American longitudinal sector deploying magnetometer in several locations. We discuss the purpose and scientific goals of the network, associated with the Low- and Mid-Latitude Ionospheric Currents and Space Weather. We provide details on the instrumentation, the inter-calibration procedure, and installations of equipments already installed. In addition, we present and discuss details on the data storage, near-real time display and availability. Finally, we provide some of the first results we already achieved from this network, including the development of new real time magnetic regional indices for South America. Contacting Author: C. M. Denardini (clezio.denardin@inpe.br)

Set-up and demonstration of a Low Energy Electron Magnetometer (LEEM)

NASA Technical Reports Server (NTRS)

Rayborn, G. H.

1986-01-01

Described are the design, construction and test results of a Low Energy Electron Magnetometer (LEEM). The electron source is a commercial electron gun capable of providing several microamperes of electron beam. These electrons, after acceleration through a selected potential difference of 100-300 volts, are sent through two 30 degree second-order focussing parallel plate electrostatic analyzers. The first analyzer acts as a monochromator located in the field-free space. It is capable of providing energy resolution of better than 10 to the -3 power. The second analyzer, located in the test field region, acts as the detector for electrons deflected by the test field. The entire magnetometer system is expected to have a resolution of 1 part in 1000 or better.

A Web Server for MACCS Magnetometer Data

NASA Technical Reports Server (NTRS)

Engebretson, Mark J.

1998-01-01

NASA Grant NAG5-3719 was provided to Augsburg College to support the development of a web server for the Magnetometer Array for Cusp and Cleft Studies (MACCS), a two-dimensional array of fluxgate magnetometers located at cusp latitudes in Arctic Canada. MACCS was developed as part of the National Science Foundation's GEM (Geospace Environment Modeling) Program, which was designed in part to complement NASA's Global Geospace Science programs during the decade of the 1990s. This report describes the successful use of these grant funds to support a working web page that provides both daily plots and file access to any user accessing the worldwide web. The MACCS home page can be accessed at http://space.augsburg.edu/space/MaccsHome.html.

Estimating the Geoelectric Field Using Precomputed EMTFs: Effect of Magnetometer Cadence

NASA Astrophysics Data System (ADS)

Grawe, M.; Butala, M.; Makela, J. J.; Kamalabadi, F.

2017-12-01

Studies that make use of electromagnetic transfer functions (EMTFs) to calculate the surface electric field from a specified surface magnetic field often use historical magnetometer information for validation and comparison purposes. Depending on the data source, the magnetometer cadence is typically between 1 and 60 seconds. It is often implied that a 60 (and sometimes 10) second cadence is acceptable for purposes of geoelectric field calculation using a geophysical model. Here, we quantitatively assess this claim under different geological settings and using models of varying complexity (using uniform/1D/3D EMTFs) across several different space weather events. Conclusions are made about sampling rate sufficiency as a function of local geology and the spectral content of the surface magnetic field.

Combined alternating gradient force magnetometer and susceptometer system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pérez, M.; Mendizábal Vázquez, I. de; Aroca, C.

2015-01-15

We report the design, fabrication, and characterization of a new system that combines the performances of two different types of magnetic characterization systems, Alternating Gradient Force Magnetometers (AGFM) and susceptometers. The flexibility of our system is demonstrated by its capability to be used as any of them, AGFM or susceptometer, without any modification in the experimental set-up because of the electronics we have developed. Our system has a limit of sensitivity lower than 5 × 10{sup −7} emu. Moreover, its main advantage is demonstrated by the possibility of measuring small quantities of materials under DC or AC magnetic fields thatmore » cannot properly be measured with a commercial vibrating sample magnetometers or AGFM.« less

Geophysics Integrated Studies in the Sun Earth System: A Cooperative Project of Vietnam, Europe, and Africa

NASA Astrophysics Data System (ADS)

Amory-Mazaudier, C.; et al.

2006-11-01

lhminh@igp.ncst.ac.vn The Hanoi Institute of Geophysics (Vietnam) will participate to international Heliophysical Year. This paper presents Vietnam‘s participation into this International cooperative project : the Vietnamese network of magnetometers, meteorological stations, ionosondes and GPS receivers involved in campaigns of measurements, the research field selected for the training of young Vietnamese scientists, and the Institutes involve in this training. This paper also presents some particularities of geophysical parameters in Vietnam : the strong amplitude of the equatorial electrojet observed by satellite data and confirmed by magnetic observations at the ground level presented for the first time to the international community, the monsoon signature etc. Finally the differences between the Asian sector and the African sector lead to the development of comparative studies between Asia and Africa.

Extended Kalman filter for attitude estimation of the earth radiation budget satellite

NASA Technical Reports Server (NTRS)

Deutschmann, Julie; Bar-Itzhack, Itzhack Y.

1989-01-01

The design and testing of an Extended Kalman Filter (EKF) for ground attitude determination, misalignment estimation and sensor calibration of the Earth Radiation Budget Satellite (ERBS) are described. Attitude is represented by the quaternion of rotation and the attitude estimation error is defined as an additive error. Quaternion normalization is used for increasing the convergence rate and for minimizing the need for filter tuning. The development of the filter dynamic model, the gyro error model and the measurement models of the Sun sensors, the IR horizon scanner and the magnetometers which are used to generate vector measurements are also presented. The filter is applied to real data transmitted by ERBS sensors. Results are presented and analyzed and the EKF advantages as well as sensitivities are discussed. On the whole the filter meets the expected synergism, accuracy and robustness.

A Wide-Angle Camera for the Mobile Asteroid Surface Scout (MASCOT) on Hayabusa-2

NASA Astrophysics Data System (ADS)

Schmitz, N.; Koncz, A.; Jaumann, R.; Hoffmann, H.; Jobs, D.; Kachlicki, J.; Michaelis, H.; Mottola, S.; Pforte, B.; Schroeder, S.; Terzer, R.; Trauthan, F.; Tschentscher, M.; Weisse, S.; Ho, T.-M.; Biele, J.; Ulamec, S.; Broll, B.; Kruselburger, A.; Perez-Prieto, L.

2014-04-01

JAXA's Hayabusa-2 mission, an asteroid sample return mission, is scheduled for launch in December 2014, for a rendezvous with the C-type asteroid 1999 JU3 in 2018. MASCOT, the Mobile Asteroid Surface Scout [1], is a small lander, designed to deliver ground truth for the orbiter remote measurements, support the selection of sampling sites, and provide context for the returned samples.MASCOT's main objective is to investigate the landing site's geomorphology, the internal structure, texture and composition of the regolith (dust, soil and rocks), and the thermal, mechanical, and magnetic properties of the surface. MASCOT comprises a payload of four scientific instruments: camera, radiometer, magnetometer and hyper-spectral microscope. The camera (MASCOT CAM) was designed and built by DLR's Institute of Planetary Research, together with Airbus DS Germany.

Non-stationary Alfvén resonator: new results on Pc1 pearls and IPDP events

NASA Astrophysics Data System (ADS)

Mursula, K.; Prikner, K.; Feygin, F. Z.; Bräysy, T.; Kangas, J.; Kerttula, R.; Pollari, P.; Pikkarainen, T.; Pokhotelov, O. A.

2000-03-01

We analyse a Pc1 pearl event observed by the Finnish search-coil magnetometer network on 15 December 1984, which subsequently developed into a structured IPDP after a substorm onset. The EISCAT radar was simultaneously monitoring the mid- to high-latitude ionosphere. We have calculated the ionospheric resonator properties during the different phases of the event using EISCAT observations. Contrary to the earlier results, we find that the Pc1/IPDP (Interval of Pulsations of Diminishing Period) frequency observed on the ground corresponds to the maximum of the transmission coefficient rather than that of the reflection coefficient. This casts strong doubts on the bouncing wave packet model of Pc1 pearls. Instead, we present evidence for an alternative model of pearl formation in which long-period ULF waves modulate the Pc1 growth rate. Moreover, we propose a new model for IPDP formation, whereby the ionosphere acts as an active agent in forming the IPDP signal on the ground. The model calculations show that the ionospheric resonator properties can be modified during the event so that the resonator eigenfrequency increases according to the observed frequency increase during the IPDP phase. We suggest that the IPDP signal on the ground is a combined effect of the frequency increase in the magnetospheric wave source and the simultaneous increase of the resonator eigenfrequency. The need for such a complicated matching of the two factors explains the rarity of IPDPs on the ground despite the ubiquitous occurrence of EMIC waves in the magnetosphere and the continuous substorm cycle.

The diverse utility of ground-based magnetometer data

NASA Astrophysics Data System (ADS)

Love, J. J.

2012-12-01

The global network of magnetic observatories represents a unique collective asset for the scientific community. Since observatory data record a wide range of physical phenomena, they are also used for a wide range of applications. Historically, magnetic observatories were first established in the 19th century to support global magnetic-field mapping projects, and this application continues to be important today. But since the dawn of the space age and the International Geophysical Year, observatory data have become important for research analysis of the ionosphere, the magnetosphere, and, indirectly, the heliosphere. Over the past couple of solar cycles, magnetic observatories have also played an important role in real-time operational monitoring of the changing conditions of space weather and assessment of ground-level geomagnetic hazards. This diversification and expansion of the observatory-data user community has brought demands for data that meet new and more stringent standards. In cooperation with the many institutes that support magnetic observatories, INTERMAGNET has been helping to coordinate and facilitate observatory modernization and improved operation. In this presentation, we give an overview of the diversity of signals recorded in observatory data, including secular, quiet, storm-time, and solar-cycle variations. We discuss future opportunities, especially for global integration and data sharing.

Global Magnetic Variability at Planetary Wave Periods

NASA Astrophysics Data System (ADS)

Forbes, J. M.; Behm, J.

2017-12-01

Planetary waves (PW) and PW-tide interactions are thought to introduce multi-day periodicities ( 2-20 days) in the electric fields and currents induced by the wind dynamo mechanism in the ionospheric E-region (ca. 100-150 km), and thus can provide important insights on coupling between the lower atmosphere and the ionosphere. Previous studies have used a relatively small subset of available data to infer the existence of these variations in ground magnetic measurements. In some cases connections were made with contemporaneous measurements of neutral wind dynamics. In the present work, we employ ground-based magnetometer data from over 100 stations from the INTERMAGNET network during 2009 to gain a global perspective on eastward- and westward-propagating and zonally-symmetric oscillations with PW periods. Our presentation describes how the unevenly-spaced global data are re-gridded onto an icosahedral grid prior to analysis, and assesses how gaps in the distribution of points across the grid affect extraction of some parts of the spectrum. Consideration is also given to possible contamination by recurrent magnetic activity at subharmonics of 27 days. The global evolution of several PW components during 2009 are depicted and interpreted.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Inhester, B.; Untiedt, J.; Segatz, M.

From two-dimensional ground magnetic and ionospheric electric field observations it should in principle be possible to estimate the two-dimensional distribution of the ionospheric conductance. The authors have developed a method to directly deduce the Hall conductance distribution {Sigma}{sub H} from ground magnetic and ionospheric electric field observations based upon some assumption for the ratio of the Hall to the Pedersen conductivity. In general, the solutions are shown not to be unique because for a specific solution the value of {Sigma}{sub H} on certain parts of the boundary of the two-dimensional domain has to be specified. However, in many situations, especiallymore » in the presence of strong and isolated field-aligned currents, these boundary values become less influential, and the solution can be shown to be practically unique over a large area of the domain. In some cases, a rather restrictive relation between the electric field and the equivalent height-integrated current density is shown to hold that could be used to cross-check the quality of the observations. As a specific example, they apply their formalism to the observation of a Harang discontinuity obtained in northern Scandinavia simultaneously by the STARE coherent radar system and the IMS Scandinavian Magnetometer Array.« less

Stanford - USGS Ultra-Low Frequency Electromagnetic Network: Hardware Developments in Magnetometer Calibration and Data Recording

NASA Astrophysics Data System (ADS)

Bowden, D. C.; Engelland-Gay, H.; Enright, A.; Gardner, J.; Klemperer, S. L.; McPhee, D. K.; Glen, J. M.

2010-12-01

Since 2006 a collaborative effort between Stanford University, the USGS, and UC Berkeley has maintained five ultra-low frequency electromagnetic (UFLEM) stations along the San Andreas Fault system. The standard site is equipped with three orthogonal coil magnetometers and two sets of orthogonal 100m electrode pairs, provides data in the 0.01- 20 Hz bandwidth, and operates alongside a broadband seismometer. We intend to use these data to characterize the generation of subsurface EM signals, and determine whether there exists a correlation to seismic activity or tectonic processes of the region. Our EM data is archived with the collocated seismic data at UC Berkeley’s Northern California Earthquake Data Center (NCEDC) and is available to the public at http://ulfem-data.stanford.edu/. Two new hardware developments in 2010 will provide more reliable calibration of our magnetic recorders, and will improve station reliability while reducing station cost. We have developed a method for calibration of buried magnetic sensor coils. As our strategy for detecting possible EM anomalies related to earthquake processes relies on comparing measured EM signals across multiple sites, it is necessary to confirm that each magnetic sensor at each site responds similarly and accurately. A portable coil placed on the ground surface, in turn above each buried magnetic sensor, generates a time-varying magnetic field of known magnitude at several different known frequencies in the bandwidth of interest. In this way, the health of each sensor can be tested and factory produced response curve verified. Signal generation and power supply for the coil is designed to be cheap (< $100), easily portable, and exactly reproducible between trials to within 95%, but does require an operator visit to each site for the measurements. In the future we intend to modify the portable system to create a winding that can be permanently installed around every magnetic sensor to provide regular calibration by a remote trigger. We have also designed, prototyped and here report results of preliminary field tests on a new data acquisition and logging system. The new system includes 8-channel A-to-D conversion, data packaging, telemetry, and power supply to components. The new system is intended to replace existing commercially-available digitizers (Quanterra) and electric-field signal conditioners (EMI, Inc.) at a fraction of their cost, while maintaining signal fidelity and system noise at levels commensurate with our ULFEM monitoring application.

Magnetometer-enhanced personal locator for tunnels and GPS-denied outdoor environments

NASA Astrophysics Data System (ADS)

Kwanmuang, Surat; Ojeda, Lauro; Borenstein, Johann

2011-06-01

This paper describes recent advances with our earlier developed Personal Dead-reckoning (PDR) system for GPS-denied environments. The PDR system uses a foot-mounted Inertial Measurement Unit (IMU) that also houses a three axismagnetometer. In earlier work we developed methods for correcting the drift errors in the accelerometers, thereby allowing very accurate measurements of distance traveled. In addition, we developed a powerful heuristic method for correcting heading errors caused by gyro drift. The heuristics exploit the rectilinear features found in almost all manmade structures and therefore limit this technology to indoor use only. Most recently we integrated a three-axis magnetometer with the IMU, using a Kalman Filter. While it is well known that the ubiquitous magnetic disturbances found in most modern buildings render magnetometers almost completely useless indoors, these sensors are nonetheless very effective in pristine outdoor environments as well as in some tunnels and caves. The present paper describes the integrated magnetometer/IMU system and presents detailed experimental results. Specifically, the paper reports results of an objective test conducted by Firefighters of California's CAL-FIRE. In this particular test, two firefighters in full operational gear and one civilian hiked up a two-mile long mountain trail over rocky, sometimes steeply inclined terrain, each wearing one of our magnetometer-enhanced PDR systems but not using any GPS. During the hour-long hike the average position error was about 20 meters and the maximum error was less than 45 meters, which is about 1.4% of distance traveled for all three PDR systems.

THOR Fluxgate Magnetometer (MAG)

NASA Astrophysics Data System (ADS)

Nakamura, Rumi; Eastwood, Jonathan; Magnes, Werner; Carr, Christopher, M.; O'Brien, Helen, L.; Narita, Yasuhito; K, Chen, Christopher H.; Berghofer, Gerhard; Valavanoglou, Aris; Delva, Magda; Plaschke, Ferdinand; Cupido, Emanuele; Soucek, Jan

2017-04-01

Turbulence Heating ObserveR (THOR) is the first mission ever flown in space dedicated to plasma turbulence. The fluxgate Magnetometer (MAG) measures the background to low frequency magnetic field. The high sensitivity measurements of MAG enable to characterize the nature of turbulent fluctuations as well as the large-scale context. MAG will provide the reference system for determining anisotropy of field fluctuations, pitch-angle and gyro-phase of particles. The design of the magnetometer consists of two tri-axial sensors and the related magnetometer electronics; the electronics are hosted on printed circuit boards in the common electronics box of the fields and wave processor (FWP). A fully redundant two- sensor system mounted on a common boom and the new miniaturized low noise design based on MMS and Solar Orbiter instruments enable accurate measurement throughout the region of interest for THOR science. The usage of the common electronics hosted by FWP guarantees to fulfill the required timing accuracy with other fields measurements. These improvements are important to obtain precise measurements of magnetic field, which is essential to estimate basic plasma parameters and correctly identify the spatial and temporal scales of the turbulence. Furthermore, THOR MAG provides high quality data with sufficient overlap with the Search Coil Magnetometer (SCM) in frequency space to obtain full coverage of the wave forms over all the frequencies necessary to obtain the full solar wind turbulence spectrum from MHD to kinetic range with sufficient accuracy. We discuss the role of MAG in THOR key science questions and present the new developments during Phase A such as the finalised instrument design, MAG relevant requirement, and new calibraion schemes.

An Arduino-Based Magnetometer

NASA Astrophysics Data System (ADS)

McCaughey, Mike

2017-05-01

An Arduino-based system with a triple axis magnetometer chip may be used to plot both the strength and direction of the magnetic field of a magnet directly on a sheet of paper. Before taking measurements, it is necessary either to correct for or to eliminate soft and hard iron effects. The same sensor may be used to determine the presence of soft iron effects.

View of the Lunar Portable Magnetometer on the LRV photographed during EVA

NASA Image and Video Library

1972-04-22

AS16-114-18433 (22 April 1972) --- View of the Lunar Portable Magnetometer mounted on the Lunar Roving Vehicle (LRV) which was parked at Station No. 2 on the Descartes lunar landing site. The Apollo 16 crew photographed it during their second extravehicular activity (EVA). Note the shadow of the astronaut taking the photograph in the left foreground.